Benadryl and nifedipine are both blood pressure-lowering drugs, the two can be taken together, the two play a therapeutic role through different physiological pathways, generally do not affect each other. However, before taking them, we must first determine whether the patient is contraindicated, if there is a contraindication, it can not be used. 1. Benadryl belongs to the angiotensin-converting enzyme inhibitors (ACEI), mainly to reduce blood pressure and reduce the cardiac load, thereby improving cardiac function, applicable to patients with hypertension and cardiac insufficiency. Major contraindications include hypersensitivity to angiotensin-converting enzyme inhibitors, history of angioneurotic edema, renal insufficiency, bilateral renal artery stenosis. Unexplained cough may occur, and also cause gastrointestinal symptoms of local irritation, heartburn, acid reflux and abdominal distension and other adverse reactions. 2. Nifedipine belongs to the calcium antagonist, mainly used for coronary angina, but also for various types of hypertension, intractable, severe hypertension also has a good effect. The use of the drug is prohibited for those who are allergic to the product and pregnant women. Adverse reactions mainly include facial flushing, headache, panic, lower extremity edema, allergy, gastrointestinal reactions, and gingival hyperplasia. In general, these two drugs are more common drugs to lower blood pressure, when a drug treatment effect is not ideal, clinically the two combined use can improve the therapeutic effect, is conducive to improving the patient’s blood pressure level, but to follow the doctor’s instructions to take, not self-medication.