Chondroitin is a chemical element extracted from animal cartilage, whose main function is to promote cartilage repair, improve joint inflammation, protect joints, and also reduce joint pain. Since chondroitin sulfate is a drug component that is a major irritant to the gastrointestinal tract, it is generally not recommended for people with severe gastrointestinal ulcers or for patients who have had upper gastrointestinal bleeding. Even for healthy adults, it is recommended to take chondroitin during meals to protect the gastric mucosa by using food wrapping and protection to prevent chondroitin from stimulating the gastrointestinal tract and causing adverse reactions such as gastrointestinal discomfort. If you take chondroitin before or after meals, you will experience stomach pain, acid reflux, nausea, vomiting or vomiting blood and a series of other uncomfortable symptoms, you need to stop taking it immediately and go to a regular hospital immediately.