Pharmacology is the study of the properties and effects of drugs and how these chemical compounds interact with living systems. There are several subdivisions of pharmacology such as pharmacodynamics, pharmacokinetics, chemotherapy, pharmacy, pharmacotherapeutics and toxicology. Toxicology has developed into a separate discipline for a variety of reasons and is covered separately. Veterinarians deal mostly with clinical pharmacology: drug actions in living animals. Clinical pharmacology is a combination of the subdivisions above, but applied more on a "practical" basis. Clinical pharmacology provides scientific methods for determining the application, dosage and toxicity of new drugs in animals. Veterinarians utilize pharmaceuticals approved for both humans and animals. Veterinarians also have an in-house pharmacy to store and dispense these drugs. Many times a drug is needed to treat a disease, but the appropriate dosage is not available in a commercial form; we utilize the help of a "compounding" pharmacist to help make the appropriate dosage form for us. This greatly aids the treatment of certain species of animals.