A 22-year-old Towson, Md., man pleaded guilty in Montgomery County Circuit Court yesterday to three drug charges stemming from the manufacture and distribution of the hallucinogenic drug LSD in Maryland, the District and Virginia.

Jeffrey Patrick Lemmon pleaded guilty before Judge John MacAuliffe to one count of conspiracy to distribute LSD, one count of possession with intent to distribute LSD and a third count, brought in Baltimore County, of possession of controlled dangerous substances with intent to manufacture LSD.

Describing the danger of LSD as comparable to that of the violence-inducing hallucinogen PCP, MacAuliffe revoked Lemmon's $101,000 bondand ordered him to await his March 29 sentencing at the Montgomery County Detention Center.

Lemmon was arrested June 26 after a six-month police undercover investigation. Police said they found 80 doses of LSD, some heroin and marijuana and $1,600 in cash on Lemmon that day.

They also found 1,300 doses of LSD at the Bethesda house where Lemmon shared a room with his girlfriend.

Lemmon's attorney said in court yesterday that he had completed a treatment program for his addiction to heroin.

A county police officer said in court yesterday that sales of LSD in the Washington-Baltimore region have dropped sharply since Lemmon's arrest.

Mike Mancuso, chief investigator in the case, called him one of the main sources in the area of LSD, or lysergic acid diethylamide, a potent drug that produces vivid hallucinations but also can inflict permanent mental damage on the user.

Under a plea agreement, drug counts against Lemmon were reduced from five to three. In addition, prosecutor Matt Campbell agreed that Lemmon would serve no more than six years in jail instead of the 15 years possible under the three counts.