Poisonous Giant Puffball: Look-alikes and the Cut Test

The giant puffball, Calvatia gigantea, is not the species behind puffball poisonings. The danger comes from three other directions:

• An Amanita egg picked by mistake. The Missouri Department of Conservation warns that the deadly destroying angel and other white mushrooms can resemble puffballs at certain stages. Holden Forests & Gardens writes that the vast majority of mushroom-related deaths are caused by Amanita species.
• An earthball. Wikipedia names the poisonous Scleroderma citrinum and immature Amanitas as the look-alikes to avoid. See poison puffball mushroom.
• An old puffball. Once the white flesh turns yellowish, greenish or brown, spores are forming; Wikipedia describes that stage as dangerous, and the Nordic Food Lab discards any specimen with discoloured or yellow-streaked flesh.

Wikipedia also notes laxative effects in some people, and the Missouri Department of Conservation mentions possible allergies. This page lists what to rule out; it does not say any puffball is safe to eat. An expert should see the actual specimen.

The Missouri Department of Conservation's instruction is to cut through any puffball from top to bottom and confirm it is pure white inside, like a marshmallow, with no sign of a cap or stem.

• Pure white, soft, even texture. Fits a young puffball.
• A faint outline of a cap, gills and stem. An Amanita egg (Nordic Food Lab; Holden Forests & Gardens). Treat it as deadly.
• Firm, hard, dark or marbled. An earthball; the Nordic Food Lab describes Scleroderma as firm and hard inside.
• A jelly layer around a folded stalk. A stinkhorn egg; see stinkhorn mushroom in yard.
• Yellow, olive, brown or purple colour. Spores are forming. A chocolate-brown or purple interior at maturity is typical of the purple-spored puffball, Calvatia cyathiformis (Wikipedia).

• Size. 8 to 20 inches wide and high according to the Missouri Department of Conservation; 10 to 50 cm, occasionally 80 cm, according to Wikipedia. The Nordic Food Lab describes a large one as bigger than a basketball but much less dense.
• Weight. The Missouri Department of Conservation says they can weigh 25 pounds or more; Wikipedia records a specimen over 23 kg (51 lb) from Thunder Bay, Ontario.
• Spores. The two references differ by a factor of a million. The Missouri Department of Conservation cites about seven trillion spores in one 15-inch specimen; Wikipedia gives about seven quintillion (7 followed by 18 zeros). Either figure means a mature puffball releases a very large spore cloud; inhaling large amounts of puffball spores is linked to a rare lung illness described on white ball mushroom in yard.

The Missouri Department of Conservation records giant puffballs from May to October in open pastures, woods and lawns, growing singly or in groups. Wikipedia describes them in meadows, fields and deciduous forests in late summer and autumn, common in the United Kingdom and North America except the southeastern United States, and protected in parts of Poland.

They feed on dead organic matter and return nutrients to the soil (Missouri Department of Conservation); a giant puffball on a lawn is not attacking the grass. The same source advises collecting puffballs only where no lawn-treatment chemicals have been used, a point worth remembering for any puffball in a treated yard.

Call Poison Control at 1-800-222-1222 (U.S.) right away, or your local emergency number. Keep any leftover piece and a photo of the cut surface, and note the time. Amanita poisoning can be silent for many hours before symptoms start, so do not wait to feel ill (Poison Control). This page does not give medical advice.

• The whole puffball beside something for scale.
• The skin close up: smooth and soft, or thick and warty.
• The cut surface through the centre, top to bottom.
• The base and the ground it grew from.

Photograph it with MushroomLens and the app suggests what it may be. A photo helps you know what to avoid; it cannot confirm a mushroom is safe to eat.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Nothing on this page says a wild mushroom is safe to eat. If you find an error, tell us and we will correct it.