Washington area residents suffering from the current round of flu and colds are being warned against taking too much medicine.

"We have had cases of children drinking medicines that smell and taste good, products used improperly and people taking the wrong medicine," said Dr. Toby Litovitz, director of the National Capital Poison Center at Georgetown University Hospital.

He said cough medicines and cold pills contain a variety of ingredients that can cause mild to severe reactions if too much is taken. These reactions can range from mild anxiety, agitation and drowsiness to severe high blood pressure, changes in heart rhythm, seizures and coma.

Litovitz warned that improper use of such products as vaporizing agents, skin salves and ointments can cause seizures. And using rubbing alcohol to bring down a child's fever has the potential to cause alcohol poisoning that could result in coma, he said.

The poison center offers two tips for safe use of medicine: Make sure you understand the dosage instructions and store medicine securely between uses so children can't get to it.

If you suspect that someone has taken too much medicine, call the poison center at 625-3333.

The best way to save on medical bills is to stay healthy.

But despite the most careful preventive steps, the typical person sooner or later must cope with the effects of an illness or injury. When that happens, the cost can be enormous. In addition to emergency treatment, there are routine medical exams and checkups intended to spot problems before they get serious. These costs also are rising.

These statistics speak for themselves. Americans today spend about $287 billion on their health--about three times as much as they spent 10 years ago.

Yet there are ways that a person can hold down expenses for doctors, hospitals and medicine. Here are five suggestions from medical authorities, including the Harvard Medical School Health Letter:

* Telephone your doctor on minor medical problems before making an appointment. He may be willing to prescribe a medicine for you over the telephone, saving you the cost of an office visit.

* When you buy over-the-counter medicine, choose the size that suits your needs. The large economy package isn't a bargain if it passes the expiration date and has to be thrown out before all the contents are used.

* Remember that all aspirin is essentially the same, except for the binders holding them together, and look for the cheapest brands.

* When your doctor prescribes a name brand drug, ask if there is a suitable generic substitute that would save you money. Also ask if the doctor has any free samples of the drug to give you in addition to or instead of the prescription.

* Medical testing can be overdone, resulting in higher than necessary bills for you. So make sure all tests scheduled for you are really necessary. "Extensive testing (blood samples, X-rays, electrocardiograms) should not automatically occur as part of each visit for the well person," according to the Harvard Medical School Letter.

How will this drug make me feel? What if I miss a dose? Can I take aspirin and drink alcohol?

Answers to these and other questions can be found in the revised edition of "About Your Medicines," a consumer reference book written in plain language that discusses most commonly used prescriptions and over-the-counter medicines.

Virginia H. Knauer, special assistant to President Reagan on consumer affairs, said the new 400-page book is a good example of the kind of information sources consumers should consult.

"A great number of consumers are injured each year by the inappropriate and unwise use of over-the-counter and prescription drugs," she said. "Much of this injury is needless and can be prevented by reading medical labels and learning about drugs from such publications as 'About Your Medicines.' "

The handbook has a suggested retail price of $4.95 and is sold at many pharmacies and health care facilities.