While not official, Clair has several categories to classify medicines. Medicines are often used to describe treatments in the Overworld, while suppressors is the term used for symptom relief.
Green Medicines are ones that eliminate the problem while producing no side effects. They are the safest medicines since they will not harm the patient they are given to.
Blue Medicines also eliminate the problem, but they can produce side effects. These side effects are harmless, so these medicines are also alright to give to most patients.
Yellow Medicines are considered a cautionary. They produce side effects that can impair the patient. These impairments will not threaten most patients lives unless severely weakened.
Orange Medicines are medicines that produce side effects that impair the patient. These side effects in uncommon situations, can become serious and potentially life threatening. This is the highest class permitted for distribution to the public, and it can only be given under the supervision of a doctor or surgeon. Considered a sensitive medicine.
Red Medicines produce side effects, where at least one can be life threatening. They are typically dosage sensitive as well. They are only used when it is a must to do so, and usage must be approved by a doctor or surgeon with necessary credentials to use such. Considered a danger medicine.
Dark Red Medicines have a suitability above fifty percent, but less than 99%. They are only used in desperate situations, often in experiments involving something with an unknown cure where alternatives are not available. Considered a severe (desperation) medicine.
Black Medicines will likely cause death (survivability under 50%). They eliminate the threat, but will likely kill the patient. They are outlawed for use unless survivability of patient without treatment is lower than that medicine's, and without other available alternatives. Certain Black Medicines, if used very carefully or concocted with another, can create a solution that may not be within this category.