Benadryl Hydrochloride can treat high blood pressure and heart failure. The main effect of Benadryl hydrochloride is to inhibit angiotensin-converting enzyme, which will eventually lead to the reduction of angiotensin in the body, play the role of vasodilator, and be able to reduce the body’s blood pressure. The main indication for Benadryl is hypertension, and because Benadryl has the effect of inhibiting ventricular remodeling, it can also be used to treat chronic heart failure. Benadryl hydrochloride also has a protective effect on the kidneys and is suitable for the treatment of patients with hypertension with heart failure and hypertension with renal insufficiency. Adverse reactions of Benadryl include cough, nasal congestion, flu-like symptoms, dizziness, headache, nausea, etc. It is contraindicated for patients who are allergic to the drug components, bilateral renal artery stenosis, lactating females during pregnancy, and patients with severe hepatic or renal insufficiency. It is recommended to take under the guidance of a physician.