| Chlorcyclizine | Organic compounds | Benzenoids | Benzene and substituted derivatives | Diphenylmethanes | Details |
| Letosteine | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Kebuzone | Organic compounds | Benzenoids | Benzene and substituted derivatives | Not Available | Details |
| Isoxsuprine | Organic compounds | Benzenoids | Benzene and substituted derivatives | Phenylpropanes | Details |
| Isoxicam | Organic compounds | Organoheterocyclic compounds | Benzothiazines | Not Available | Details |
| Isoconazole | Organic compounds | Benzenoids | Benzene and substituted derivatives | Benzylethers | Details |
| Isoaminile | Organic compounds | Benzenoids | Benzene and substituted derivatives | Phenylpropanes | Details |
| Iotroxic acid | Organic compounds | Benzenoids | Benzene and substituted derivatives | Benzoic acids and derivatives | Details |
| Iopanoic acid | Organic compounds | Phenylpropanoids and polyketides | Phenylpropanoic acids | Not Available | Details |
| Iopamidol | Organic compounds | Benzenoids | Benzene and substituted derivatives | Halobenzenes | Details |
| Iodamide | Organic compounds | Benzenoids | Benzene and substituted derivatives | Benzoic acids and derivatives | Details |
| Inositol nicotinate | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Hexacarboxylic acids and derivatives | Details |
| Indoramin | Organic compounds | Organoheterocyclic compounds | Indoles and derivatives | Tryptamines and derivatives | Details |
| Indoprofen | Organic compounds | Phenylpropanoids and polyketides | Phenylpropanoic acids | Not Available | Details |
| Indenolol | Organic compounds | Benzenoids | Indenes and isoindenes | Not Available | Details |
| Indalpine | Organic compounds | Organoheterocyclic compounds | Indoles and derivatives | Indoles | Details |
| Ifenprodil | Organic compounds | Organoheterocyclic compounds | Piperidines | Benzylpiperidines | Details |
| Ibuproxam | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Monoterpenoids | Details |
| Hydroxydione | Organic compounds | Lipids and lipid-like molecules | Steroids and steroid derivatives | Hydroxysteroids | Details |
| Hexoprenaline | Organic compounds | Benzenoids | Phenols | Benzenediols | Details |
| Hexetidine | Organic compounds | Organoheterocyclic compounds | Diazinanes | Not Available | Details |
| Hexamethonium | Organic compounds | Organic nitrogen compounds | Organonitrogen compounds | Quaternary ammonium salts | Details |
| Azosemide | Organic compounds | Organoheterocyclic compounds | Azoles | Tetrazoles | Details |
| Glibornuride | Organic compounds | Lipids and lipid-like molecules | Prenol lipids | Monoterpenoids | Details |
| Glafenine | Organic compounds | Organoheterocyclic compounds | Quinolines and derivatives | Aminoquinolines and derivatives | Details |
| Gemeprost | Organic compounds | Lipids and lipid-like molecules | Fatty Acyls | Fatty alcohols | Details |
| Fusafungine | Organic compounds | Organic acids and derivatives | Peptidomimetics | Depsipeptides | Details |
| Fursultiamine | Organic compounds | Organoheterocyclic compounds | Diazines | Pyrimidines and pyrimidine derivatives | Details |
| Dimetotiazine | Organic compounds | Organoheterocyclic compounds | Benzothiazines | Phenothiazines | Details |
| Fominoben | Organic compounds | Benzenoids | Benzene and substituted derivatives | Anilides | Details |