It is **Extremely unreliable and dangerous** To determine whether a drug is doped with other substances only by color or smell. The drug itself is highly dangerous, and the adulterated substance may further increase its toxicity or unpredictability, and even fatal. The following information is only used for popularization of knowledge. **It is strongly recommended to stay away from drugs and seek professional help**. --- ###**Unreliable sensory judgment method (with serious limitations)** 1. **Color change** -Drugs of higher purity (such as heroin and cocaine) may appear as white or light-colored powders/crystals, but many adulterated substances (such as talcum powder, starch, caffeine) may also appear of a similar color. -Some dopants (such as fentanyl) are white in themselves and cannot be distinguished by the naked eye. -When the drug manufacturing process is rough, it may appear gray, brown or yellow, but this does not mean that it is necessarily doped. 2. **Odor difference** -Some drugs have a special smell (such as the grassy smell of cannabis and the pungent chemical smell of meth), but the smell may be masked or mixed after other substances are incorporated. -Many adulterants (such as sugar and flour) are odorless and cannot be recognized by smell. --- ###**Common risk substances doped** -**Cheap fillers**: Starch, talcum powder, flour (increase volume, but may cause allergies or lung damage). -**Additives to enhance the effect**: Fentanyl (which can be fatal in a very small amount), caffeine, and anesthetics (such as lidocaine). -**Toxic chemicals**: washing powder, rat poison, insecticides (reduce cost, but extremely toxic). --- ###**Important Warning** 1. **Unreliable sensory detection** Changes in color or odor may be caused by factors such as storage conditions and manufacturing processes, and are not necessarily related to doping. For example： -Cannabis may appear gray-green due to mildew, not doped. -Ecstasy pills (MDMA) have a variety of colors, and the composition cannot be judged by their appearance. 2. **Fatal risk** Synthetic opiate drugs such as fentanyl can be fatal in as little as 2 mg, and may be mixed into heroin, cocaine or even counterfeit prescription drugs, which cannot be identified by the naked eye. 3. **Legal and health consequences** Possession or testing of drugs is illegal in itself, and exposure to drugs may lead to addiction, poisoning, or death. --- ###**Reasonable action to be taken** 1. **Absolutely avoid contact with drugs** and do not rely on any “self-testing” methods. 2. **When doping is suspected, immediately contact a professional institution (such as a public health department or a drug control agency) and use specialized analytical equipment (such as a mass spectrometer) for testing. 3. **In case of emergency** (such as overdose or poisoning), immediately call the emergency number and inform the substances you may be exposed to. --- Please keep in mind: **There is no family method to safely detect the composition of drugs**. The only way to protect lives is to stay away from drugs and seek professional support when needed.