苄青霉烯酰聚赖氨酸：以聚赖氨酸为载体、含苄青霉烯酰成分(苄青霉素的主要抗原块定簇)的皮试抗原，以划痕或皮内试验法测试对青霉素的过敏性。- 4-hydroxyphenylpyruvate dioxygenase
- 5,10-methylenetetrahydrofolate reductase
- 5-aminolevulinate synthase
- 5-bromodeoxyuridine
- 5-bromouracil
- 5'-deoxyadenosyl transferase
- 5-formyltetrahydrofolate cycloligase
- 5-FU
- 5-HIAA
- 5-HT
- 5-hydroxyindoleacetic acid
- 5-hydroxytryptamine
- 5-methyltetrahydrofolate-homocysteine meth-yltransferase
- 5-oxoprolinase (ATP hydrolyzing)
- 5-oxoproline
- 5-oxoprolinuria
- 5-ribosyluridine
- 606
- 6-aminopenicillanic acid
- 6-azauridine
- 6-mercaptopurine
- 6-MP
- 6-phytase
- 7,12-dimethylbenz anthracene
- 7-aminocephalosporanic acid