The May Apple has flowered in my back yard every year since 1978. It develops very quickly during the warmer days of spring and plants that flower develop a single berry (apple) in August. You can can eat the ripe berries in limited amounts, even though they may be mildly toxic. I've never tasted them but 'they' say the flavor is bland and resembles an overripe melon. Not my cup of tea.
The totally ripened fruit which forms from the May Apple blossom is edible and is said to make a pretty good jam or jelly if properly prepared. The last I looked it was still not part of the Smucker catalog, probably with good reason. However, the unripened fruit and all other parts of the plant (rhizome, foliage, roots and seed) are poisonous at worst and cathartic (look it up) at best. May Apple contains podophyllotoxin, a cytostatic, and is used topically in the treatment of viral and genital warts as well an ingredient in a couple of cancer treatment drugs.
PetPoisonHelpline.com says that podopyllotoxin is easily absorbed through tissue. When pets accidentally ingest or 'contact' this plant, May Apple can result in both gastrointestinal (e.g., vomiting, diarrhea, drooling) and dermal irritation. My dogs and cats have walked through, on, under, but never around large clones of it on a daily basis for years--all spring and summer--and have never shown any noticeable ill effects. I have never seen my pets nibble or dig in the areas of these plants. However, death has been known to occur in animals such as swine that dig up and eat the highly toxin roots. We have no pigs