Investigators looking into the deaths of four people allegedly treated with aloe vera by a Manassas doctor have followed a trail of desperate hopes of the sick and dying to the Baltimore offices of Allen Hoffman.

From his bare-walled sales office, Hoffman has acted as an enthusiastic supplier and promoter of the plant extract, which is approved in the United States as a diet supplement but not as a drug. He has touted the substance as a dramatically effective treatment for diseases ranging from cancer to AIDS, and he has promoted the benefits of injecting the mixture directly into the body, which is legal in some countries but not in the United States.

Hoffman and partner Neal Deoul say they simply are distributing a legal nutritional supplement, sold under the name "T-UP," meant to be swallowed by the teaspoonful with juice. They say that they advise physicians that injecting aloe is illegal in this country and that they don't sell it for use intravenously in humans. And they say they can't be blamed if a "crazy" doctor in Manassas ordered the substance pumped into someone's veins, as Virginia authorities allege Manassas physician Donald L. MacNay did.

But Hoffman, who refers to the "magic of aloe vera," has not only made medical claims about an unapproved drug. He has, according to others, offered U.S. physicians an injectable solution of it.

Two doctors have said in interviews that Hoffman discussed administering aloe through injection or intravenously. Both said Hoffman offered to sell them a sterile and filtered version of his product for that purpose, in addition to the unfiltered liquid to be taken orally. And The Washington Post has obtained a bottle with a T-UP label that is rubber-stoppered and sealed, the type commonly used to hold injectable substances. The label -- which doesn't identify the solution inside the bottle -- says "filtered and sterilized." The bottle was provided by an employee at a doctor's office who said that it is aloe and that it came from Hoffman's company, T-UP Inc. Hoffman denies that it came from his company.

Hoffman has promoted aloe vera as "possibly the greatest single advancement in the history of medicine" and has made sweeping claims of its effectiveness against AIDS, cancer, lupus, diabetes, herpes and other ills.

In a tape sent to prospective customers as recently as last month, Hoffman criticized U.S. restrictions on injecting the substance and said he had taken ill people outside the country to receive injections.

Hoffman said he distributes his aloe vera mixture for the satisfaction of saving people from the grip of organized medicine, which he said suppresses information about the plant's benefits for the sake of profits.

"It is really gratifying; I've had tears in my eyes to have somebody call up and say, I gotta tell you, my dad was dying, and all we did was take aloe vera . . . and you know what, I beat 'em, I beat 'em,' " Hoffman related on his promotional tape.

In interviews, Hoffman acknowledged that he advocates injectable aloe vera as a treatment for many diseases, but he said he is careful to tell physicians and others that it is illegal to do it in the United States.

"This is done overseas," Hoffman said. "That is why when I was interviewed by the {Food and Drug Administration} I told them that if they look at anything we publish, we tell people you cannot do this in the United States of America."

Aloe vera is a cactus-like plant and member of the lily family that has been used since the time of the ancient Egyptians for its healing properties on the skin. The FDA has said its extract can be taken orally as a nutritional supplement.

But no one selling the substance is permitted to make claims about aloe's medical benefits because those claims are unproven, according to the FDA. And anyone injecting aloe by a needle or intravenously into a patient is breaking the law because the substance isn't an approved drug, according to authorities.

On the tape, Hoffman said aloe, combined with a mineral, cesium chloride, eats away malignant cells and will make cancer "disappear." He said it also permits people with AIDS to "live a normal life" and produces benefits for people with various other ailments, including multiple sclerosis, arthritis, herpes, lupus, pneumonia and emphysema.

He noted that the FDA does not allow intravenous use of aloe, "so we simply take folks who are extremely ill, take them out of the country, and we will give this substance orally, we will give it intravenously, we will inject it directly into the tumors."

Hoffman's partner, Deoul, said that the promotional tapes have been destroyed and that T-UP Inc. no longer sends out brochures. He said that the company's new attorney has told the partners they were in "technical violation" of FDA regulations with such promotions and that they have stopped.

"Accuse us of ignorance. We didn't know we couldn't do that," Deoul said.

Investigators are trying to determine whether aloe played a role in the deaths of four men who visited MacNay, an orthopedic surgeon with offices in Manassas and Annandale. Each of the men had terminal cancer.

The Virginia Board of Medicine's order suspending MacNay's license includes allegations that two of the men died after receiving intravenous treatments of aloe, for which they paid MacNay $12,000. A search warrant filed by the Virginia State Police alleged a third patient died after receiving aloe treatment costing $12,000. The treatment was given intravenously, the man's family said in interviews. The fourth patient allegedly took aloe orally, the Board of Medicine's order said.

MacNay declined to answer questions for this article. In an earlier interview, he declined to talk about individual patients but complained that the suspension of his license was unfair.

The Virginia Board of Medicine has scheduled a formal administrative hearing for Nov. 20 "to receive and act upon evidence" that MacNay may have broken laws governing the practice of medicine. Investigations also are being conducted by the FDA, the Drug Enforcement Agency and the Virginia State Police.

Maryland officials said they are investigating whether Hoffman has practiced medicine without a license, but authorities wouldn't give details of the inquiry.

No criminal charges have been filed against MacNay or Hoffman. MacNay's assistant, Ronald R. Sheetz, has been charged with practicing nursing without a license.

After the news that MacNay patients had died, Hoffman said in an interview that he had supplied MacNay with the substance but for oral use only. "We sold him aloe -- lots and lots of aloe," he said.

"The last thing I want is my name associated with this guy," Hoffman said at the time. "We sell nutrition supplements to thousands of people across the world. Can you imagine a drugstore {being liable if it} sells aspirin and some foolish person misuses the aspirin and takes a whole bottle? . . . I have nothing to do with this. We provide aloe vera juice. It's just plain aloe vera juice, chock-full of minerals."

He added, "You have one crazy character that did something crazy," referring to MacNay.

Hoffman, who said he has a PhD in reproductive biology, has identified himself as a "former researcher" at Johns Hopkins University. Officials at Johns Hopkins said they have no record of his association with the university or hospital since 1979, and they are checking their records for prior years.

Two years ago, Hoffman contacted AIDS patients in Baltimore and convinced many that his T-UP aloe mixture offered them a cure, according to Lynda Dee, president of AIDS Action Inc. In an interview at that time with WJZ-TV in Baltimore, Hoffman insisted that "we are destroying the HIV virus."

Deoul, who said he retired from the electronics industry, said he and Hoffman recently incorporated T-UP and moved into an office in the Woodholme Medical Building, a new building with dozens of doctors' offices. There were few medical trappings in his office, which last week was occupied by several employees who manned telephones in cubicles.

Deoul said they sell only an oral liquid that contains visible plant pulp and clearly is not for injection. The company has "absolutely not" sold a sterile or filtered solution for intravenous use, Deoul said initially. He later said the company may have arranged to sell "five or 10 bottles" of intravenous liquid to veterinarians for use on animals.

Two U.S. physicians, who said in interviews that they bought oral aloe from Hoffman, said he told them that intravenous solutions also were available.

"He has two forms -- an intravenous form and a suppository or oral form," said John Thompson, a doctor of osteopathic medicine in Las Vegas.

"I told him I didn't want to do it by IV -- I'm not set up for that," said Ruth Miller, a doctor of osteopathy in Tulsa. "I don't recall him talking about whether that was illegal. But I didn't ask the question. It didn't come up."

Neither Hoffman nor Deoul could be reached to respond to the two doctors' statements. After a reporter talked to Hoffman several times by telephone and made arrangements for a face-to-face interview, Hoffman's attorney canceled the interview and said his client would have no more comment.

Deoul answered some questions the next day when a reporter went to T-UP's offices, but he referred further questions to his attorney. The attorney, Anthony L. Young, of the Baltimore firm of Piper and Marbury, said he would have no comment. Staff writers Jerry Knight and Eric Lipton and Metro resource director Margot Williams contributed to this report. ** EXCERPTS FROM T-UP PROMOTIONAL TAPE

Excerpts from Allen Hoffman's promotional audiotape "There Is Hope," which until recently was being distributed by Hoffman's company, T-UP Inc., along with aloe vera products. INTRAVENOUS USE

"The FDA has looked at aloe vera quite extensively, and what the FDA has said is, Well, Allen, you can let people drink aloe vera. It's a natural substance, it's a health food, but you can't inject it into people.' "So we simply take folks who are extremely ill, take them out of the country, and we will give this substance orally, we will give it intravenously, we will inject it directly into the tumors, and we will utilize cesium chloride. "I just got back from Costa Rica. I had a lady that mainstream medicine gave up on. They said this is a lady who's going to die. . . . And so when we got to Costa Rica . . . within 10 days we reduced one tumor by 40 percent, one tumor by 19 percent. . . . But more than that -- I had radiologists who were simply staring at this with their jaws open -- we stimulated the production of new, healthy tissue. . . . "It appears that she is close to being absolutely normal. One of the most exciting things I've ever seen. . . . " CANCER AND AIDS

"My experience recently is that within 10 days, 50 percent of a malignancy will disappear. The rest of the malignancy, based upon scientific literature, should disappear within two to three months. Very exciting. "I . . . gave it to three people who were HIV-affected and who were obviously quite weak. They were debilitated. Three weeks after having done that, we had three folks who were literally jogging around the clinic. "If we get to treat some of these {AIDS patients} for 18 months, approximately 50 percent of these people will sero-convert. . . . If a blood test is taken, it will be negative. "You have the people who developed AZT, who have done work in it, and they are saying, don't use AZT anymore, use this stuff that Allen Hoffman has." OPPOSITION

"The government is not happy to see this, the HMOs are not happy to see it. . . . "In this country, an oncologist may spend as much as 15 years after high school training. Can you imagine what would happen if we presented a simple way to destroy malignancies and we emptied his office? "Pharmaceutical industry isn't really very fond of me these days. . . . Incidentally, this is a natural substance. It can't be patented. So there is no drug company that is willing to take it on. You can't make money out of it. . . . So pharmaceutical companies have no interest in this. You may find a rare oncologist who is interested in giving away all his patients. I haven't found any yet." CAPTION: ALLEN HOFFMAN