Concomitant use of herbs with synthetic drugs has become a practice in order to treat or cure certain illnesses. These herbal medicines available in the market have no accessible literature on the side effects or toxicities it might cause. To determine the effect of concomitant use of a common herbal juice drink consisting of twenty three botanicals on Losartan potassium, six rabbits were induced with hypertension using a high-fat diet. Then, three of them were given with Losartan potassium with herbal juice drink while the other three with Losartan potassium alone. Plasma concentrations were analyzed using High Performance Liquid Chromatography. After fourteen days of treatment, the results showed that there was no significant difference on the plasma concentrations of the rabbits given with Losartan potassium alone and Losartan potassium with herbal juice drink. Also, the herbal juice drink was analyzed with Fourier Transform Infrared Spectroscopy. FTIR results showed that the herbal juice drink is composed primarily of amines.