(-)-Ketoconazole is primarily used as an antifungal medication to treat a variety of fungal infections. It is effective against conditions such as athlete's foot, ringworm, and yeast infections, including those caused by Candida species. The compound works by inhibiting the synthesis of ergosterol, a crucial component of fungal cell membranes, leading to cell death.

In dermatology, it is often applied topically in the form of creams, shampoos, or gels to treat skin and scalp infections. For systemic infections, it can be administered orally, though this is less common due to potential side effects on the liver.

Additionally, (-)-Ketoconazole has been explored for its anti-androgenic properties, making it useful in managing conditions like Cushing's syndrome and certain types of hormone-dependent cancers, such as prostate cancer. It inhibits the production of androgens by interfering with steroidogenesis, which can help control symptoms in these conditions.

In veterinary medicine, it is also employed to treat fungal infections in animals, particularly in pets like dogs and cats. Its broad-spectrum antifungal activity makes it a versatile option in both human and animal healthcare.