The following question was asked of a marja`:
When it is established with certainty that drinking carbonated drinks/soft drinks is harmful, at that point does drinking them become impermissible?
Thank you very much for taking the time to answer the question.
The marja,` Imam `Abdur-Rahman Ash-Shami, may Allah preserve him, answered with what follows:
When it is established by the statement of a body of trustworthy specialists that carbonated drinks/soft drinks do indeed cause harm, then at that point they do indeed become impermissible to drink.
The same position holds when the ingredients are shown to contain primarily impermissible things, i.e. alcohol and the like.
Taken from the website of the maraji`