Student Q: Can I use Lactaid on Passover?

Here is a question about using Lactaid milk/pills on Passover. My answers includes a lot of information about why we can eat some foods without Kosher-for-Passover symbols as long as they are Kosher and bought before Passover.

Since many students have medical issues, are lactose intolerant, or are not that familiar with the rules of Passover, I was given permission to share this with you.

Rabbi Bruce,

So I have a few questions regarding food that is kosher for Passover. I've become lactose-intolerant and soy-intolerant in the last year, and know that soy milk isn't kosher for Passover which is fine. I've been trying to research what is kosher and what isn't, but want to get a Conservative rabbi's view on the matter. The Orthodox Union says that lactaid milk is kosher as long as it is bought before Passover, do you think ___ stash of lactaid milk would have been bought beforehand? Is this a stringency or something you would hold to? Are lactaid pills kosher for Passover? The OU said that chewable pills aren't, but are the non-chewable ones? I've never been too stringent about this, but am trying to be more stringent. Thanks for your help!
Sincerely, R

R,
Thanks for writing. First, the only dairy meals we will have will be
student-cooked breakfasts in Dawes Kosher K. There will also be some
dairy products out at breakfast in Cutter-Ziskind.
Do you mind me posting your question and my answer on my blog (w/o
your name)? it may interest other students.
RB

I will start with my answer and then give you an explanation (that has
to be fairly long).
If you buy Lactaid yourself, you should follow what the OU says. If I
buy Lactaid for use of Jewish students, I would do so as well. Smith
Kosher dining would do so if it bought milk for Passover (it may buy a
small amount but the meals are all meat/pareve). People often forget
that Smith is not Jewish and the campus is not a Jewish home (although
your room and the Kosher K are considered to be Jewish spaces).
Unless you have reason to believe that Lactaid has Chametz (and not
potential or accidental Chametz--see below) as an ingredient, then it
should be fine for you to drink. I will see what we can do to have
enough in advance.
Pills often contain non-listed ingredients used to make the shape,
capsule, etc. If a pill is important, necessary, etc., I take it on
Passover regardless of the ingredient. I would not advise taking
vitamins, minerals, unless you have a serious issue that requires it
daily. lactaid pills are complicated. If you don't eat dairy, you
don't need to have them. Even at most dairy meals, you can avoid it
by eating other foods.
Do you eat meat, chicken, fish? If not, I can see where you would
need dairy for protein. If that is the case, let me know.

Let me explain to you why the OU said what they said about Lactaid.
First the basics and then the Passover differences. Regarding
year-round (ie. non Passover) Kosher items, there is a difference
between accidental and intentional mixing of kosher and un-kosher
items (kosher meat and pork) or kosher items that are not permitted to
mix (such as milk and meat).
Any intentional mixing is not permitted. For unintentional mixing,
you have to remove anything visible (ie. a visible piece of shrimp in
a fish stew) but can use the rest as long as the forbidden is 1/60 or
less (remember that in the ancient world they counted in 60ths--we
still do for time).
We are not allowed to eat, cook, or derive benefit of mixtures of milk
and meat. We are allowed to possess it.

Regarding Chametz on Passover, the Torah uses the language of removing
Chametz from your possession: " by the first day all chametz shall
have been removed from your home." This adds a few stringencies to
Chametz which does not exist with other non-Kosher foods: in addition
to the three prohibitions above, we can not possess it. To accomplish
that, one searches for chametz, donates or uses it, puts aside
anything not being donated, and then sells the rest to no longer have
ownership. In many haggadot, there is a prayer to say during the
search for chametz and a different version during the burning. This
nullifies any chametz you do not know about, missed, etc. It does not
apply to actual chametz you might eat (you can't do this and then have
a bagel on Passover) but it applies to non-listed Chametz in items
such as milk, sugar, pure juice, etc. If you buy something before
Passover and nullify the Chametz (which I usually do for Smith's
Jewish community), those items are fine for Passover since any
accidental crumbs or unlisted ingredients are nullified. Once
Passover begins, we can no longer nullify such items. The sources say
Chametz found on Passover is Chametz even to the smallest possible
amount imaginable.

Rabbi Bruce