Hi, Colsprin 100 is a medication that contains aspirin, which is a nonsteroidal anti-inflammatory drug (NSAID). It is commonly used to reduce fever, relieve pain and inflammation, and prevent blood clots. However, like any medication, it can cause side effects. Some common side effects of Colsprin 100 tablets include: - Gastrointestinal upset such as nausea, vomiting, and stomach pain. - Allergic reactions such as hives, rash, and difficulty breathing. - Increased risk of bleeding or bruising due to the blood-thinning properties of aspirin. - Tinnitus is a ringing or buzzing sound in the ears. - Headache, dizziness, or confusion. Reye s syndrome (a rare but serious condition that can occur in children with a viral infection who are given aspirin). If you experience any of these side effects or any other unusual symptoms while taking Colsprin 100, it is important to notify your doctor immediately. It is also important to note that aspirin may interact with other medications, so it is important to inform your doctor of any other medications you are taking before starting treatment with Colsprin 100. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician