All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Islamic law (Sharia) prohibits anything that leads to the loss of reason or impairs its capabilities, as reason is the basis of accountability that Allah has honored humans with. Impairing reason leads to the destruction of the five necessities, which are: the preservation of religion, life, progeny, intellect, and wealth. Among the things that impair reason are drugs, which cause mental disturbance and impair its strength. Moreover, they lead to the destruction of other necessities that Islam ensures to protect. The harm of drugs is widespread, affecting both individuals and society. Therefore, the consumption, trafficking, and promotion of drugs are among the gravest prohibitions. Trading in drugs is considered corruption on earth as it leads to the loss of security, the decay of values, and the disintegration of families.
Among the evidence for the prohibition of drugs is the saying of Allah: {O you who have believed, indeed, intoxicants, gambling, [sacrificing on] stone alters [to other than Allah], and divining arrows are but defilement from the work of Satan, so avoid it that you may be successful} [Al-Ma'idah: 90]. Drugs share the same reason for prohibition as intoxicants, which is causing intoxication by impairing the mind, so they fall under the same ruling and can be analogized to them. Another verse states: {And makes lawful for them the good things and prohibits for them the evil} [Al-A'raf: 157], and drugs are among the evil things. Allah also says: {And do not throw [yourselves] with your [own] hands into destruction} [Al-Baqarah: 195]. One of the fundamental principles in Islam is to avoid everything harmful to human health, and drug consumption leads to physical, psychological, and social harm.
From the noble Sunnah, it is narrated from Umm Salama (may Allah be pleased with her) that she said: "The Messenger of Allah (peace and blessings be upon him) forbade every intoxicant and narcotic" (Narrated by Ahmad and Abu Dawood). Drugs, in their various forms, are either intoxicants or narcotics. The Prophet (peace and blessings be upon him) also said: "Every intoxicant is khamr (wine), and every intoxicant is haram (forbidden)" (Narrated by Bukhari).
Sheikh al-Islam Ibn Hajar al-Asqalani (may Allah have mercy on him) said: "He (the Prophet) used the absolute statement 'every intoxicant is forbidden' as evidence for the prohibition of anything that causes intoxication, even if it is not a drink. This includes substances like hashish and others. Al-Nawawi and others have definitively stated that it causes intoxication. Some others argue that it is a narcotic, but this isn`t a valid view, as it induces sensations similar to the pleasure, exhilaration, and addiction caused by alcohol, according to the subjective experiences. There is a clear prohibition in Abu Dawood's narration concerning every intoxicant and narcotic." (Fath al-Bari, Vol. 10, p. 45). Al-Hafiz Ibn Hajar commented on the hadith narrated by Abu Dawood from Umm Salama, saying: "The hadith of Umm Salama, narrated by Abu Dawood with a good chain, states: 'He forbade every intoxicant and narcotic.'" (Fath al-Bari, Vol. 10, p. 44).
The scholars have explicitly stated this matter. It is mentioned in [Hashiyat Ibn Abidin, Vol. 3, p. 239]: "The Shafi'i and Hanafi scholars agree that divorce occurs if one loses their sanity due to consuming hashish, based on their fatwa declaring its prohibition." Also, in Hashiyat Ibn Abidin [Vol. 6, p. 457], it is stated: "Consuming bang, hashish, and opium is prohibited because it corrupts the mind, distracts from the remembrance of Allah and prayer... Some people have used it and their minds were corrupted, and it may even lead to death." In [Mughni al-Muhtaj, Vol. 4, p. 187]: "The scholars have mentioned in the section on foods that consuming hashish is forbidden."
It is obligatory for someone afflicted with intoxicants or drugs to quit them immediately and seek help from medical professionals and specialists to overcome the withdrawal symptoms associated with quitting. Imam al-Shirwani, may Allah have mercy on him, said: "Indeed, it is obligatory for the one afflicted with drugs to strive to eliminate the need for them either by using their antidotes or gradually reducing their intake until they no longer harm him by quitting." [Hashiyat al-Shirwani 'ala al-Tuhfah, Vol. 9, p. 168].
Sheikh al-Islam Ibn Hajar al-Haytami, may Allah have mercy on him, stated that those who have engaged in drug use must gradually reduce their intake, as this gradual reduction is a method to wean the liver off its attachment to it until quitting it entirely does not harm them. This is the consensus among distinguished physicians. If they do not strive to gradually reduce their intake, they are considered sinful transgressors without excuse. [Tuhfat al-Muhtaj, Vol. 9, p. 168].
In conclusion, the effects resulting from drug abuse are destructive to both individuals and society, conflicting with the principles and rulings of Islamic law and its wisdom. Consequently, their ruling is prohibition. Likewise, trading in drugs, whether through selling, buying, smuggling, marketing, or profiting from them, is all forbidden, as anything that leads to what is forbidden is itself forbidden. And Allah the Almighty knows best.