Substance and Toxicity databases

If you find some chemical in a test tube and you don't know what it is. Then here are a good list of places to check the effects and considerations online.

Toxic substances lists

Agency for Toxic Substances & Diseases Registry http://www.atsdr.cdc.gov/substances/index.asp

Toxic substances portal

Access the most important information about toxic substances and how they affect our health

http://www.atsdr.cdc.gov/toxguides/index.asp

ToxGuides http://www.atsdr.cdc.gov/toxguides/index.asp

Food Safety

list of Food Safety Hazards Guidebook

Drugs and Medicine

US Food and Drug Administration http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm

Drugbank is a searchable bioinformatics and chemoinformatics resource http://www.drugbank.ca/

Chemicals and substances

ChemSpider http://www.chemspider.com/