The unique physical, emotional, and developmental characteristics of the growing child make dental care particularly challenging for the practitioner. Children are not simply small adults, and the principles of adult pharmacotherapeutics are not easily extrapolated to \"fit\" the profile and needs of the child. This chapter explains pharmacological considerations in pediatric dentistry. It explains various rules of drug dosages, i.e. clark’s rule, young’s rule, cowling’s rule and many other rules.