We investigated the effect of drugs (dapsone, paracetamol, and isoniazid) on the production of reactive oxygen and halogen species by neutrophils. The standard fluorescent method using scopoletin as well as recently developed fluorescent methods using oxazine dyes, celestine blue B, and gallocyanine were employed for this purpose. Celestine blue B reacts selectively with hypochlorous acid, while gallocyanine reacts mainly with the superoxide radical-anion, which reveals the regulatory effect of anti-inflammatory drugs on neutrophil NADPH-oxidase and myeloperoxidase responsible for the production of reactive oxygen and halogen species, respectively. These results indicate that gallocyanine and celestine blue B hold promise as chemosensors for studying the effect of drugs used in anti-inflammatory therapy for the neutrophil respiratory burst.