Griseofulvin is an antifungal drug. It is used both in animals and in humans, to treat ringworm infections of the skin and nails. It is derived from the mold Penicillium griseofulvum.

Griseofulvin is usually taken once a day or can be taken two to four times a day. Although your symptoms may get better in a few days, you will have to take griseofulvin for a long time before the infection is completely gone. It is usually taken for 2 to 4 weeks for skin infections, 4 to 6 weeks for hair and scalp infections, 4 to 8 weeks for foot infections, 3 to 4 months for fingernail infections, and at least 6 months for toenail infections.
Do not take more or less of it or take it more often than prescribed by your doctor.

Common side effects may include:
headache
upset stomach
vomiting
diarrhea or loose stools
thirst
fatigue
dizziness
faintness
If you experience any of the following symptoms, call your doctor immediately:
fever
sore throat
skin rash
mouth soreness or irritation

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

In case of overdose, call your local poison control center. If the victim has collapsed or is not breathing, call local emergency services.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Griseofulvin is used to treat skin infections such as jock itch, athlete's foot, and ringworm; and fungal infections of the scalp, fingernails, and toenails.

Store this medication at room temperature and away from excess heat and moisture (not in the bathroom). Keep the liquid away from light. Do not freeze.

Tell your doctor:
if you are allergic to griseofulvin, penicillin, or any other drugs.
what prescription and nonprescription medications you are taking, especially anticoagulants such as warfarin (Coumadin), oral contraceptives, cyclosporine (Neoral, Sandimmune), phenobarbital (Luminal), and vitamins.
if you have or have ever had liver disease, porphyria, lupus, or a history of alcohol abuse.
if you are pregnant, plan to become pregnant, or are breast-feeding.
(If you become pregnant while taking griseofulvin, call your doctor.)
if you drink alcohol.
You should plan to avoid prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Griseofulvin may make your skin sensitive to sunlight.