Toxic nitrogen oxides and chloride gases. Chloramphenicol is a white or colorless needle-like or flaky crystal, which produces toxic nitrogen oxides and chloride gases after combustion. Chloramphenicol is a broad-spectrum antibiotic produced by Streptomyces, and natural chloramphenicol is levorotatory. The synthetic product is white or light yellow needle-like or flaky crystal, odorless.