Fungicide, also called antimycotic, any toxic substance used to kill or inhibit the growth of fungi. Fungicides are generally used to control parasitic fungi that either cause economic damage to crop or ornamental plants or endanger the health of domestic animals or humans. Most agricultural and horticultural fungicides are applied as sprays or dusts. Seed fungicides are applied as a protective covering before germination. Systemic fungicides, or chemotherapeutic, are applied to plants, where they become distributed throughout the tissue and act to eradicate existing disease or to protect against possible disease. In human and veterinary medicine, pharmaceutical fungicides are commonly applied as topical anti-fungal creams or are given as oral medications.