Short answer
Impaction is a blockage in the gut. Signs are no droppings or constipation, a bloated belly, lethargy, loss of appetite and weight loss. Common causes are insects that are too big or too hard, low temperatures, dehydration, parasites, and swallowing unsuitable substrate. Check the warm-end temperature and water first, but call a reptile vet promptly if your gecko is bloated or has not passed droppings: severe cases can need surgery.
Signs to watch for
The RSPCA says abnormal droppings or constipation together with weight loss can be serious.5
What causes it
ReptiFiles lists the usual causes:1
- Insects that are too big
- Low temperatures
- Dehydration
- Parasites
- Underlying illness
The Vet Desk adds eating too many hard-shelled insects.4
The substrate question
VCA says never to use coarse sand, corncob bedding or crushed walnut shell, because they can be swallowed and block the intestines.2 Reptiles Magazine’s vet author lists sand, ground walnut shell and fine gravel as substrates that can cause impaction.3
ReptiFiles disagrees about sand. It argues that food-related impaction is more common, and that substrate impaction only happens when a gecko is already ill from a low basking temperature, dehydration or parasites.1 Our substrate guide sets out both views.
What to do
- Call a reptile vet if your gecko is bloated, lethargic or has not passed droppings. ReptiFiles notes that surgery may be needed in severe cases.1
- Check the setup: warm-end floor temperature, water, and the size of the insects you feed.14
- Do not give oil, laxatives or force-feed unless your vet tells you to.
Some keeper guides, including ReptiFiles, describe warm baths and gentle belly massage for mild cases.14 Ask your vet before relying on them, since the signs of impaction overlap with other illnesses.
Prevention
- Keep the warm end warm enough. Low temperatures slow digestion.1 See our temperature guide.
- Size insects correctly: no bigger than the space between the gecko’s eyes.4
- Vary the insects rather than relying on one or two types.3
- Keep fresh water out.4
- Feed from a dish if you use loose substrate.
- Test for parasites with a yearly fecal check.
Common questions
Does sand cause impaction in leopard geckos?
Sources disagree. VCA warns against coarse sand, and Reptiles Magazine's vet author lists sand among substrates that can cause impaction if swallowed. ReptiFiles argues that food-related impaction is more common and that substrate impaction only happens in geckos that are already ill.
Should I give my gecko oil for impaction?
Not without a vet's advice. ReptiFiles suggests a drop of olive or mineral oil by mouth, but we found no veterinary source recommending it, and the signs of impaction overlap with other illnesses. Call a vet first.
Can mealworms cause impaction?
Too many can. The Vet Desk links impaction to eating too many hard-shelled insects, though it still recommends mealworms and crickets as a low-risk diet. Keep insects no larger than the space between the eyes. Reptiles Magazine's vet author advises a varied diet rather than one or two insect types.
Sources
Numbers in the text link to these sources. We checked each one on the date shown.
- 1Leopard Gecko ImpactionReptiFiles. Checked Oct 29, 2026.
- 2Leopard Geckos: Care and FeedingGregory Rich, DVM. VCA Animal Hospitals. Checked Oct 29, 2026.
- 3Leopard Gecko Lizards Not EatingMargaret A. Wissman, DVM, DABVP. Reptiles Magazine. Checked Oct 29, 2026.
- 4Leopard Gecko Not EatingEd Malaker, reviewed by Dr. Paola Cuevas, MVZ. The Vet Desk. Checked Oct 29, 2026.
- 5How to care for a leopard geckoRSPCA. Checked Oct 29, 2026.
Update history
- : First published.
- : Re-checked every claim against its sources; corrected wording, numbers and attributions.
HerpWise Editorial · About the author and review process
HerpWise Editorial summarizes published veterinary, welfare and specialist care guidance. The sources and check date are listed on each guide. Veterinary review is credited separately when completed.
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