The principle of the similitude, the basis of homeopathy, has correspondences in the clinical studies of secondary effects of many modern pharmaceutical agents through the observation of the rebound effects of these drugs. Through clinical pharmacology, I proposed a model on which to base the scientificism of the homeopathic model. We have studied the effects of the drugs in the human body using pharmacological compendia and recent scientific works, confirming the mechanism of the homeopathic medicines' action through the verification of the primary action of the drugs and the consequent secondary reaction of the organism in hundreds of pharmaceutical agents. Treatment exploiting the "rebound" effect (curative vital reaction) may also be observed. This work suggests a research methodology to scientifically base the therapeutic principle of similitude.