Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
You should not use St. John’s wort if you find halal alternatives. Otherwise, you are allowed to use it.
Responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
If you have effective halal alternatives, then you should not use the St John’s Wort. Otherwise, you may use it. The scholars are divided on the use of medicines with gelatin ingredients.
One group, including some of the members of the World Islamic Medical Association, permits the use of these medicines based on the principle of Istihalah. According to this principle, if an ingredient, otherwise considered haram, has undergone a chemical transformation so that it has been altered drastically, then it is no longer considered haram; instead, it becomes lawful. That is the case with alcohol turned into vinegar; while alcohol is haram, vinegar is halal. They say: The same is the rule with gelatin used in medicines.
Another group of scholars, however, differ as they consider that the chemical transformation of gelatin in medicines does not undergo a complete change; as such, it cannot be deemed as wholly pure and lawful. It becomes doubtful. We are to avoid that which is questionable.
The former group, however, has some strong arguments:
Are we to indulge in such nitpicking and hair-splitting when the Prophet (peace be upon him) was opposed to practicing rigidity?
The use of gelatin is so pervasive that it becomes hard to avoid it altogether. Therefore, another fiqhi rule can be used here: the rule of Umum al-Balwa, which states that when something is so pervasive, and it is hard to avoid, the law can be relaxed. The Prophet asserted in no uncertain terms, “this religion is easy to practice; whoever makes it hard will be defeated by it.”
To conclude, you should not use St. John’s Wort if you find halal alternatives. Otherwise, you are allowed to use it.
Almighty Allah knows best.