In the consideration of potent versus mild suppression of gastric acid secretion in the treatment of peptic ulcer disease, it must be remembered that pharmacological effect in terms of degree of suppression of acidity is closely linked to therapeutic efficacy in terms of numbers of ulcers healed. More potent degrees of suppression of acidity result in faster ulcer healing. Moderate suppression of acidity, such as is achieved by the H2RA, can heal just as many ulcers if treatment is continued longer. Mild acid suppression will take still longer to produce the same healing rates. Therapeutic benefit of any treatment must be assessed also in terms of the side-effect profile of the drug or drugs used. There is an enormous cumulative experience with the H2RA as a group and they are known to have an excellent safety profile.