White or a kind of white to yellowish crystalline powder, smell-less or slight smelly. 289 ¡ãC decompounds, slightly soluble in water, does not dissolve in the ethyl alcohol;Dissolves in the diluted acid or the diluted alkali, the long timeillumination will color up; heat together with water can produce the water a small amount of indole, like when heat up under the sodium hydroxide, the cupric sulfate existence, then will produce massive indole; heats up with the acid in the hidden place will be more stable; when coexist with Medicine bulk drugs, carbohydrate, and aldehyde, it is extremely easy to decompose.