This weakens the doctor's argument. Even if the herbs themselves don't directly harm patients, in many cases, they take the place of remedies proven to be effective. This undermines the doctor's claim that patients will not be harmed by the prescription of these remedies.

This doesn't weaken the argument. The doctor has already told us that there isn't much evidence for the effectiveness of these remedies. The argument is based on the lack of harm and the possibility of benefit from these herbs, not on whether or not they are marketed truthfully.

This is too vague to weaken the argument. We don't know how many \"some\" patients are, or whether the medicines discussed here are even herbal medicines. This statement looks like it applies to medicines in general. Even if some patients are allergic to herbal medicines, this isn't an argument against allowing the prescription of such remedies. Such patients could simply avoid the herbal medicines in favor of more conventional options .

Irrelevant. The doctor's conclusion is based on the lack of harm and possibility of benefit from these medicines, not on the motives of people who provide them.

This doesn't weaken the argument. The doctor's argument is about the effects of these herbs, not their biochemical properties. She just says that these herbs don't cause harm and may help. Even if they are a placebo, they can still provide relief.