Nitazoxanide 500 mg is an antiparasitic and antiviral medication used to treat certain infections that cause diarrhea, including loose and watery bowel movements. It is commonly prescribed for infections caused by protozoa such as Giardia lamblia and Cryptosporidium parvum. These parasites often cause gastrointestinal issues like persistent diarrhea, especially in people with weakened immune systems. Nitazoxanide works by interfering with the energy production of these parasites, effectively stopping their growth. It’s generally well-tolerated, but common side effects may include stomach pain, headache, or nausea. It is important to take the full course as prescribed to ensure complete recovery.