| Cytidine | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleosides | Not Available | Details |
| Dimethylglycine | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Citric acid | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Tricarboxylic acids and derivatives | Details |
| Cytidine monophosphate | Organic compounds | Nucleosides, nucleotides, and analogues | Pyrimidine nucleotides | Pyrimidine ribonucleotides | Details |
| Choline | Organic compounds | Organic nitrogen compounds | Organonitrogen compounds | Quaternary ammonium salts | Details |
| D-Xylose | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
| L-Cystathionine | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Deoxyadenosine | Organic compounds | Nucleosides, nucleotides, and analogues | Purine nucleosides | Purine 2'-deoxyribonucleosides | Details |
| Galactitol | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
| Ethanol | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Alcohols and polyols | Details |
| Gamma-Aminobutyric acid | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Glycerylphosphorylethanolamine | Organic compounds | Organic acids and derivatives | Organic phosphoric acids and derivatives | Organic phosphoramides | Details |
| Glycolic acid | Organic compounds | Organic acids and derivatives | Hydroxy acids and derivatives | Alpha hydroxy acids and derivatives | Details |
| Homovanillic acid | Organic compounds | Benzenoids | Phenols | Methoxyphenols | Details |
| Glyoxylic acid | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Carboxylic acids | Details |
| Folic acid | Organic compounds | Benzenoids | Phenols | Methoxyphenols | Details |
| D-Glucose | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
| Glycine | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Fructose 6-phosphate | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
| Glutathione | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Glycerol 3-phosphate | Organic compounds | Lipids and lipid-like molecules | Glycerophospholipids | Glycerophosphates | Details |
| D-Glucuronic acid | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
| Guanidoacetic acid | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Amino acids, peptides, and analogues | Details |
| Homogentisic acid | Organic compounds | Benzenoids | Benzene and substituted derivatives | Phenylacetic acids | Details |
| Glycerol | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
| Guanine | Organic compounds | Organoheterocyclic compounds | Imidazopyrimidines | Purines and purine derivatives | Details |
| Guanosine | Organic compounds | Nucleosides, nucleotides, and analogues | Purine nucleosides | Not Available | Details |
| Fumaric acid | Organic compounds | Organic acids and derivatives | Carboxylic acids and derivatives | Dicarboxylic acids and derivatives | Details |
| Glycocholic acid | Organic compounds | Lipids and lipid-like molecules | Steroids and steroid derivatives | Bile acids, alcohols and derivatives | Details |
| Glyceric acid | Organic compounds | Organic oxygen compounds | Organooxygen compounds | Carbohydrates and carbohydrate conjugates | Details |
