| Aniline dyes |
| Antimalarials |
| Benzene derivates |
| Dapsone, rasburicase and phenazopyridine |
| Inadequately cooked vegetables contaminated with bacteria |
| Local anaesthetics (benzocaine, prilocaine, lidocaine) |
| Nitric and nitrous oxides |
| Nitrites |
| Nitroglycerine |
| Nitroprusside |
| Paraquat |
| Phenacetin |
| Phenytoin |
| Silver nitrate |
| Smoke inhalation |
| Sodium valproate |
| Sulfasalazine |
| Sulfonamides |
| Zopiclone |