This thesis is an investigation of the normal canine gastric acid profile and the degree of gastric acid suppression achieved using antisecretory drugs. Continuous 24-hour intragastric pH measurements were obtained in fasted and fed dogs. Thereafter, a randomized, multiple cross-over study compared saline IV q12h, ranitidine 2mg/kg IV q12h, famotidine 0.5mg/kg IV q12h, pantoprazole 1mg/kg IV q24h, and omeprazole ~1mg/kg PO q24h, for 7 days. Recordings were obtained on Day 0, 2, and 6. Next, famotidine 0.5mg/kg IV q8h and omeprazole suspension (~1mg/kg) PO q12h were evaluated in 6 dogs. The median pH and the percent time pH >= 3 and pH >= 4 were compared. Fasting produced greater acid suppression than feeding. Famotidine, pantoprazole and omeprazole showed significant acid suppression based on median 24-h pH and percent time pH >= 3 and >= 4. Omeprazole suspension q12h was the most effective at suppressing gastric acid secretion.