| beta-Mercaptolactate-Cysteine Disulfiduria |  | Disease | Pyridoxal phosphate / Pyruvic acid / Adenosine phosphate / Glutamic acid / Cysteine / NADH / ATP / Iron / Zinc / gamma-Glutamylcysteine / Pyrophosphoric acid |
| beta-Ureidopropionase Deficiency |  | Disease | L-Glutamine / ATP / Calcium / Magnesium cation / Iron / Zinc / 5-O-phosphono-alpha-D-ribofuranosyl diphosphate / Thymidine monophosphate / Dihydrouracil / Dihydroorotic Acid / Orotic acid / Cytidine-5'-Triphosphate / Uridine / Orotidylic acid / Ribose-1-Phosphate / beta-Alanine / Flavin adenine dinucleotide / Flavin mononucleotide / Uracil / Uridine-5'-Diphosphate / Thymine / Uridine monophosphate / Deoxyuridine monophosphate / Pyrophosphoric acid / N-Carbamoylaspartic acid / Thymidine |
| Betahistine H1-Antihistamine Action |  | Drug action | Calcium / Betahistine |
| Betaine Metabolism |  | Metabolic | Tetrahydrofolic acid / Ademetionine / Choline / Methionine / NADH / ATP / Adenosine / Potassium cation / Magnesium cation / Zinc / N,N-dimethylglycine / Flavin adenine dinucleotide / Pyrophosphoric acid / Betaine aldehyde |
| Betaxolol Action Pathway |  | Drug action | ATP / Betaxolol / Potassium cation / Calcium / Magnesium cation |
| Betazole Action Pathway |  | Drug action | ATP / Betazole / Potassium cation / Zinc / Acetylcholine |
| Bevacizumab Action Pathway |  | Drug action | Bevacizumab |
| Bevantolol Action Pathway |  | Drug action | ATP / Bevantolol / Potassium cation / Calcium / Magnesium cation |
| Bilastine H1-Antihistamine Action |  | Drug action | Calcium / Bilastine |
| Bile Acid Biosynthesis |  | Metabolic | Glycine / NADH / ATP / Iron / Taurine / Mesoheme / Cholic Acid / Flavin adenine dinucleotide / Palmitic Acid / Pyrophosphoric acid / Taurocholic acid / Cholesterol / Chenodeoxycholic acid / Taurochenodeoxycholic acid |
| Biotin Metabolism |  | Metabolic | Biotin / Lysine / ATP / Pyrophosphoric acid |
| Biotinidase Deficiency |  | Disease | Biotin / Lysine / ATP / Pyrophosphoric acid |
| Bisoprolol Action Pathway |  | Drug action | ATP / Bisoprolol / Potassium cation / Calcium / Magnesium cation |
| Bivalirudin Action Pathway |  | Drug action | Bivalirudin / Phylloquinone / Calcium |
| Blue Diaper Syndrome |  | Disease | Cysteine / Potassium cation / Urea |
| Bopindolol Action Pathway |  | Drug action | ATP / Potassium cation / Calcium / Magnesium cation / Bopindolol |
| Bosutinib Inhibition of BCR-ABL |  | Drug action | Bosutinib |
| Bromfenac Action Pathway |  | Drug action | Glutamic acid / Glutathione / Dinoprostone / Bromfenac / Calcium / Magnesium cation / Zinc / Prostaglandin D2 / Mesoheme / Prostaglandin G2 / Arachidonic Acid |
| Bromodiphenhydramine H1-Antihistamine Action |  | Drug action | Bromodiphenhydramine / Calcium |
| Brompheniramine H1-Antihistamine Action |  | Drug action | Brompheniramine / Calcium |
| Buclizine H1-Antihistamine Action |  | Drug action | Buclizine / Calcium |
| Bumetanide Action Pathway |  | Drug action | Cysteine / Bumetanide / Potassium cation / Urea |
| Bupivacaine Action Pathway |  | Drug action | ATP / Bupivacaine / Norepinephrine / Dopamine / Potassium cation / Calcium |
| Bupranolol Action Pathway |  | Drug action | ATP / Potassium cation / Calcium / Magnesium cation / Bupranolol |
| Buprenorphine Action Pathway |  | Drug action | ATP / Norepinephrine / Buprenorphine / Dopamine / Potassium cation / Calcium |