Happi 20 Tablet contains Rabeprazole 20 mg, a proton pump inhibitor used to reduce gastric acid secretion. It is indicated for the treatment of gastroesophageal reflux disease (GERD), erosive esophagitis, Zollinger-Ellison syndrome, and peptic ulcer disease. Rabeprazole acts by irreversibly inhibiting the H+/K+ ATPase enzyme system at the secretory surface of gastric parietal cells, thereby suppressing the final step of acid production. This leads to decreased gastric acidity, promoting healing of acid-related lesions and relief from associated symptoms such as heartburn, acid regurgitation, and epigastric pain. Happi 20 is typically administered orally once daily, preferably before meals, with dosage and duration tailored according to the clinical condition and physician’s discretion. It is generally well tolerated; common adverse effects may include headache, diarrhea, nausea, and abdominal discomfort. Caution is advised in patients with hepatic impairment, and long-term use should be monitored due to potential risks such as vitamin B12 deficiency and increased susceptibility to gastrointestinal infections. Happi 20 should not be co-administered with drugs requiring an acidic environment for absorption without medical supervision. Patients should inform their healthcare provider of any concomitant medications or underlying health conditions prior to initiation.