Pharmacology: It is a science which involves in study of drug action on living organisms such as animals, organs or tissues. It deals with the form of drugs dosage to be administrated, physiological action, biological action and side effects etc.Enteral routes:The drugs are administrated through the alimentary tract (gastrointestinal tract) called enteralroutes of administration of drugs.Oral - Drugs are administrated by mouthRectal - Drugs are administrated through the anal portal into the rectum or lower Intestine.Buccal - Drugs are kept between the surfaces of the tooth adjacent to the cheek or beneath the tongue.