| Astringents and Deodorants | Not Available | 4 | 2 | Details |
| ATP Binding Cassette Transporter, Subfamily B, Member 1 | Not Available | 1 | 5 | Details |
| ATP Binding Cassette Transporter, Subfamily B, Member 1, antagonists & inhibitors | Not Available | 2 | 4 | Details |
| ATP-Binding Cassette Transporters | A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport o... more | 1 | 0 | Details |
| ATP-Binding Cassette, Sub-Family C Proteins | A sequence-related subfamily of ATP-BINDING CASSETTE TRANSPORTERS that actively transpo... more | 2 | 1 | Details |
| Atrial Natriuretic Factor | Not Available | 1 | 3 | Details |
| Atropine Derivatives | Analogs and derivatives of atropine. | 2 | 13 | Details |
| Autacoids | A chemically diverse group of substances produced by various tissues in the body that c... more | 69 | 229 | Details |
| Autologous Cellular Immunotherapy | Not Available | 7 | 6 | Details |
| Autologous Cultured Cell | Not Available | 8 | 7 | Details |
| Autologous Hematopoietic Stem Cell-Based Gene Therapy | Genetic therapy consisting of autologous hematopoietic stem cells (HSCs). | 5 | 6 | Details |
| Autonomic Agents | Agents affecting the function of, or mimicking the actions of, the autonomic nervous sy... more | 225 | 1295 | Details |
| Autonomic Ganglionic Blocker | Not Available | 2 | 5 | Details |
| Avermectines | Not Available | 1 | 12 | Details |
| Aversive Agents | Chemicals added to pharmacologic preparations, poisonous household goods, and other che... more | 1 | 4 | Details |
| Aza Compounds | Organic chemicals where carbon atoms have been replaced by nitrogen atoms. | 73 | 281 | Details |
| Azabicyclo Compounds | Bicyclic bridged compounds that contain a nitrogen which has three bonds. The nomenclat... more | 42 | 182 | Details |
| Azadirachta | Not Available | 1 | 1 | Details |
| Azarabine and Derivatives | Not Available | 0 | 0 | Details |
| Azaspirodecanedione Derivatives | Not Available | 1 | 12 | Details |
| Azasteroids | Steroidal compounds in which one or more carbon atoms in the steroid ring system have b... more | 3 | 19 | Details |
| Azepines | Seven membered heterocyclic rings containing a NITROGEN atom. | 19 | 74 | Details |
| Azetidines | Not Available | 1 | 3 | Details |
| Azetines | Cyclic compounds that include atoms other than carbon in their ring structure. | 26 | 79 | Details |
| Aziridines | Saturated azacyclopropane compounds. They include compounds with substitutions on CARBO... more | 4 | 7 | Details |