O2 Tablet is a combination medicine containing ofloxacin (an antibiotic) and ornidazole (an antiprotozoal/antibacterial). It is used to treat bacterial and parasitic infections, such as diarrhea, dysentery, and other intestinal infections. It works by killing the infection-causing organisms and preventing their growth. Take it as prescribed and complete the full course to ensure effective treatment. Avoid alcohol during treatment and for a few days after stopping the medicine, as it may cause unpleasant effects. Common side effects include nausea, dizziness, stomach pain, and headache. Use O2 Tablet with caution in people with liver problems, neurological disorders, or a history of tendon problems.