Selling haraam and
    doubtful things
Question

                Assalamu alikum. I understand that selling
      haram things are probihibited. If I have a grocery store and I sell soaps, toothpastes etc
      that contain haram or doubtful ingredients, shall I commit sin? Thanks.
Praise be to Allah.It is not permissible to sell them because when Allaah
    forbids a thing He also forbids its price. Ibn ‘Abbaas (may Allaah be pleased with
    them both) said: “The Messenger of Allaah 
 (peace and blessings of Allaah be upon
    him) said: ‘Allaah has cursed the Jews because fat was forbidden to them, but they
    sold it and took its price. When Allaah forbids something he also forbids its
    price.’” (Reported by Imaam Ahmad, 2546).
    With regard to doubtful things, it is better not to sell
    them, so as to be free of any blame, as the Prophet 
 (peace and blessings of Allaah be
    upon him) said. Al-Nu’maan ibn Basheer said: “I heard him saying, ‘I heard
    the Messenger of Allaah 
 (peace and blessings of Allaah be upon him) say: “What is
    permitted is clear and what is prohibited is clear, and between them are doubtful things
    which many people do not know about. Whoever avoids doubtful things will be on the safe
    side with regard to his religion and his honour, but whoever falls into doubtful things
    will fall into haraam things.”’” (Reported by Muslim, 2996). And Allaah is the Source of Strength