Side effects of Famotidine mainly include facial flushing, bloating, and lack of appetite. Contraindications mainly include pregnant women, etc. It is mostly used to relieve stomach pain, heartburn sensation (heartburn), acid reflux caused by excessive stomach acid. 1. Side effects: mainly include circulatory system manifestations such as increased pulse rate and facial flushing; digestive system manifestations such as abdominal distension, nausea, vomiting, diarrhea and constipation; and central nervous system manifestations such as headache, fatigue, somnolence, anxiety, hallucinations, and rapid speech. Some patients may also have allergic reactions, menstrual irregularities, facial edema and tinnitus and other adverse reactions. 2. Contraindications: Contraindicated in pregnant and lactating women. In addition, it is contraindicated in patients with severe renal insufficiency. The use of specific drugs should be under the guidance of a doctor. If there is any discomfort, it is recommended to consult a doctor in time for treatment.