Amphotericin B is an antifungal antibiotic commonly used in cell culture to prevent and treat fungal contamination. It works by binding to ergosterol in the fungal cell membrane, creating pores that disrupt the cell’s integrity and lead to cell death. Amphotericin B is often added to culture media to protect cells from fungal growth without harming the cells themselves. However, its use is generally limited due to its potential toxicity to mammalian cells at higher concentrations.