For Pharmaceutical & Drug Information refer to :

RxList
Yahoo! Health Medication or Drug
RxMed Pharmaceuticals Index
Infomed Drug Guide
Mayo Clinic Medicine Center including USP Drug Information
Drug Information Database
Pharmaceutical Information Network Home Page
e-pharmacy Rx advisor
DIDX llc.'s Adverse Drug Interaction Search Engine
DrugDB
Therapeutics Initiative
Drug Formulary, University of Wisconsin
Internet Self-Assessment in Pharmacology (ISAP)
Physicians' GenRx
The University of Maryland Drug Information Service (UMDI)
Martindale's Virtual Pharmacy Center
University of Manchester (UK) Pharm Web
The World-Wide Web Virtual Library: Pharmacy
U.S. Pharmacopeia
WebMD Drug Reference