Medicines are the subject of some of the most common questions on Pesaḥ. For example, there is concern that pills contain wheat-based starch. The purpose of the starch is to solidify and harden the pills. Had the starch been produced from potatoes or kitniyot, there would be no problem even for Ashkenazim, as for medicinal purposes one may swallow pills containing kitniyot. But what about starch extracted from a type of grain that can become ḥametz? It must be emphasized that a dangerously ill person whose treatment requires eating ḥametz has a mitzva to eat ḥametz. Saving a life overrides the prohibition against eating ḥametz. The question applies to an ill person whose life is not at risk.
The answer depends on the taste of the medicine: if it is flavored, like syrup, lozenges, or chewables, then one must ascertain that it is kosher for Pesaḥ. In cases of uncertainty, it is forbidden to ingest them. Under pressing circumstances, if there is no way to clarify the uncertainty, one may be lenient (see the note).
However, if the medicine is bitter or tasteless to the point that it is not fit as food, it may be swallowed on Pesaḥ. Even if the starch was derived from wheat, since it has been mixed with various bitter substances it is inedible and has lost its status as ḥametz. As we have seen, ḥametz that was rendered unfit for a dog’s consumption before Pesaḥ is no longer considered ḥametz and may be kept on Pesaḥ. The fact that one wants to swallow the medicine does not demonstrate that the ḥametz in the medicine is important to him, since the medicine, not the ḥametz, is significant for him, and the ḥametz itself is bitter and unfit for consumption. The ḥametz in it is thus batel and not prohibited (Ḥazon Ish, Mo’ed 116:8; Igrot Moshe, OḤ 2:92).
Some meticulously observant people try to avoid even bitter medicines that contain ḥametz. They show concern for the opinion of the few poskim who maintain that medicine is not considered unfit for a dog’s consumption since we deem it significant, and it is thus rabbinically prohibited. Other poskim permit swallowing bitter medicines that contain ḥametz starch for one who is bedridden or whose entire body is in pain, but rule stringently for one suffering from mild aches and pains. But the view of most poskim is that bitter medicines containing ḥametz starch may be taken by any ill person and even only to reduce mild pain, as a prophylactic, or to fortify the body.
Practically speaking, if one is uncertain whether certain bitter or tasteless medicines contain wheat starch, he may swallow them without checking that they are free of wheat starch. As we have learned, most poskim maintain that medicines rendered unfit for a dog’s consumption before Pesaḥ may be consumed during Pesaḥ even if they are known to contain ḥametz. Even one who prefers to comply with the stringent opinion on this issue need not be strict if he is uncertain whether the medicine contains ḥametz. This is especially true nowadays, when we know that potato and corn starch are used more widely than wheat starch. Thus, in practice, one may consume bitter or tasteless medicines on Pesaḥ without ascertaining whether they contain ḥametz. When one knows for certain that a particular medicine contains ḥametz starch, he may choose to rely on the lenient opinion of most poskim or the stringent minority.
Moreover, even when the starch is from wheat flour, it generally did not have time to rise, and at worst would be classified as ḥametz nuksheh, which did not undergo a complete leavening and is only rabbinically prohibited. Since this ḥametz nuksheh is part of a mixture within a bitter pill, there is no reason to be stringent. Nevertheless, some incline toward stringency (Arugat Ha-bosem 2:99, and Atzei Ha-Levanon §19). Some have written that although these pills are technically permitted, the holy people of Israel are strict even about ḥametz mixed into a bitter pill (Tzitz Eliezer 10:25:20). But Nishmat Avraham OḤ 1:466:1 states that most pills do not contain ḥametz at all. It is further stated there in the name of R. Ovadia Yosef that even though he writes in Yeḥaveh Da’at 2:60 that only a genuinely sick person may be lenient, if it is uncertain whether or not the pill contains ḥametz, there is no need to ascertain. As noted, the vast majority of poskim maintain that it is not at all prohibited to swallow a bitter pill, and even one with a minor ailment may take a pill that contains ḥametz rendered unfit for a dog before Pesaḥ started.
A tasty medicine requires kosher certification. However, under pressing circumstances, and when it is uncertain whether there is ḥametz in this medicine and there is no way to clarify (generally because companies guard the composition of medicines like a trade secret), since the vast majority of medicines do not contain ḥametz, one may be lenient based on the majority, as explained in SA YD 110:3. Regarding concern for a prohibited substance in tasty medicines, I wrote in Peninei Halakha: Kashrut 37:8 that if there is no medicine with kosher certification, one may take a tasty medicine without kosher certification. However, in the present case, due to the stringency of the prohibition of ḥametz, I wrote that one may be lenient only under pressing circumstances.