"Hey Siri, did I take my metformin" gets you a web search, or "I don't understand," instead of an answer from the app that actually has that information. It feels like a bug. Almost always, it's one of a small number of specific reasons — the same ones regardless of which medication app you're using, because they come from how Siri's App Shortcuts work, not from any one app's bugs.
You left out the app's name
This is the most common cause by far, and it's not a quirk of one app — it's an Apple requirement. Every phrase an app registers with Siri has to include the app's name, or Apple's own build tools reject the app before it can ship. "Take my metformin" won't reach any app. "Take my metformin in Doz" will, because the app name is literally how Siri decides which of the many apps on your phone might handle that sentence.
If a phrase doesn't include the app's name, it isn't a bug — it structurally cannot work, on any app, on any current iOS version.
You asked it in your own words instead of the registered phrase
Siri's newer free-form understanding (branded as Siri AI on recent iOS versions) can route open-ended requests to apps, but only for a fixed set of built-in domains — messages, timers, that kind of thing. There is currently no domain for medication tracking, so a medication app can only be reached through the exact phrases it registered, not through open conversation about the same topic.
That doesn't mean the wording has to be perfectly rigid — Siri tolerates ordinary grammatical variation — but it does mean a phrase missing a key word can fail to match even when it sounds equivalent to you. "When did I take acetaminophen" and "When did I take my acetaminophen" are not guaranteed to be treated the same; a small word like "my" changes whether the phrase matches at all. If your own phrasing isn't working, check the app's own list of supported phrases rather than assuming the feature is broken.
Siri hasn't learned the name yet
If you just added a new medication and Siri says it doesn't recognize the name, that's usually timing, not a dead end. The list of names Siri can match against is cached by iOS, and an app has to explicitly tell the system to refresh it every time your medication list changes. That refresh is near-instant but isn't guaranteed to land before your very next sentence. Wait a few seconds after saving a new medication before asking Siri about it by name.
You named something that's no longer active
Asking about a medication you've already stopped or archived can produce a response that sounds like a miss — "that one's archived" rather than the answer you expected — because the app can see the name but knows it's not currently tracked. That's usually a sign the medication should either be un-archived in the app, or that you meant to name a different, active one.
The action needs a subscription you don't have
Some medication apps separate what's free from what's paid at the level of individual Siri actions, not just app-wide — reading your schedule might be free while logging a dose by voice requires a paid tier. If a Siri action consistently gives a polite refusal rather than doing anything, that's worth checking before assuming Siri itself is malfunctioning.
Where to find the phrases that actually work
Guessing a plausible-sounding phrase and hoping is the wrong approach for any app — the working phrases are a fixed, finite list, and every app that supports Siri should be able to show you that list directly rather than leaving you to reverse-engineer it.
How this works in Doz
All five causes above are things Doz specifically accounts for: every phrase includes "Doz" by design, a medication you've just added becomes sayable within seconds because Doz refreshes the list itself, asking about an archived medication gets a direct "that one's archived" rather than a false "I couldn't find it," and read actions (schedule, stock, streak, last dose) are free while write actions (logging, skipping, refilling, archiving) are part of Doz Pro.
Settings → Siri & Shortcuts inside Doz lists every phrase it understands, word for word, so there's nothing to guess. The phrases themselves are laid out here if you want the full list before you start talking to your phone.
The short version
A Siri shortcut that doesn't respond almost always comes down to a missing app name, a phrase that doesn't match closely enough, a medication Siri hasn't caught up on yet, or an action gated behind a subscription. None of that is a stray bug — it's how the underlying framework works on every app that uses it, so the fix is the same everywhere: check the app's own list of exact phrases rather than guessing.
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