# Limitations of judging the purity of drugs I understand that you may be asking this question for safety or educational purposes. However, I need to point out that it is a very unreliable method to judge the purity of drugs by visually observing the color or smell. The reasons are as follows： -Many additives or dopants may be colorless and odorless -Professional drug dealers often use additives that mimic the characteristics of pure products - Even trace amounts of dopants can cause serious health risks **Safety advice**: The only reliable method is professional chemical testing, not sensory judgment. If you are worried about drug safety issues, I suggest： -Use only prescription drugs obtained from formal channels -Consult a medical professional -Learn about professional drug testing services If you have an academic interest in drug composition analysis, it is recommended to consult professional toxicology or forensic science materials for scientific information.