Celery's one real hazard: the strings
Celery is not toxic to guinea pigs, and most will crunch it happily, but it comes with a mechanical catch that few other vegetables have. A celery stalk is built from long, tough fibres, and when a guinea pig bites through a long piece, those strings can trail, tangle around the teeth and make swallowing awkward, occasionally causing a pig to gag or struggle with a mouthful it cannot manage. The fix takes seconds: slice the stalk across its length into short pieces, around a centimetre or so, so no long fibre survives the cut. Prepared that way, celery loses its only real drawback and becomes a safe, crunchy addition to the vegetable bowl. Handing over whole or half stalks, by contrast, is the one way this mild vegetable causes trouble.
What celery actually contributes
Nutritionally, celery is mostly water, which makes it refreshing and filling without being fattening, a genuinely useful trait in a species prone to gaining weight. It brings some vitamin C, which guinea pigs need from their food, along with smaller amounts of other vitamins and minerals, but the levels are modest rather than outstanding, so celery should support the menu rather than carry it. Think of it as a supporting vegetable: bell peppers and leafy greens remain the dependable daily source of vitamin C, while celery adds crunch, variety and hydration alongside them. The leaves at the top of the stalk are fine to feed too and are often eaten with more enthusiasm than the stalk itself, so do not trim them away as waste.
Portions and how often
A few short pieces, offered a couple of times a week as one element of that day's mixed vegetables, is a good working portion for an average adult guinea pig. Because celery is so watery, generous servings can loosen droppings in some pigs, which is another reason moderation suits it better than daily handfuls. Introduce it gradually if your pig has never had it, as with any new vegetable, and wash stalks well before chopping, since celery's grooves hold grit and garden soil tenaciously. Serve it fresh and remove uneaten pieces later the same day, because watery vegetables wilt and spoil faster in a warm enclosure than hay or dry food does.
Reactions worth watching
Most guinea pigs take to prepared celery without incident, but watch the first few servings. Persistently soft droppings after celery days mean the portion is too generous for that pig, so cut it back rather than abandoning the vegetable outright. A pig who picks out everything else and leaves the celery is simply expressing a preference, and there is no need to persist with a vegetable he dislikes when so many others exist. As with any feeding question, the red flags are never really about celery at all: a guinea pig who stops eating, hides away or produces no droppings needs a veterinarian promptly. For the ordinary healthy pig, celery chopped short is a small, safe pleasure in the weekly rotation.
Watery vegetables are easiest to keep in proportion when the week's feeding is visible at a glance, and KinsLe's Care Teams let the household share one feeding record, so celery appears as the occasional crunchy extra it is meant to be.