Toxic Parts:
steroidal alkaloids, tropane alkaloids, nitrates
Flower Color:
  • flower color
  • flower color
  • flower color
woodlands, haybales, meadows

Time of Greatest Risk


Geographical Distribution

Nightshades distribution - United States

Related Species


Solanum spp

Black Nightshade, European Bittersweet, Climbing Nightshade, Dogwood, Felonwood, Poison Berry, Scarlet Berry, Carolina Horsenettle
6/ 10
Nightshade plants (Solanaceae) consist of over 70 different species of flowering plants. Nightshades are native to North America and range from weedy shrubs to small trees. They are considered weeds and often found growing in cultivated fields, gardens, waste places and overgrazed pastures. Nightshade plants are one of the more common contaminants in poor quality hay.

Nightshade Toxic Components

Nightshade plants contain Solanaceae alkaloids, also known as glycoalkalids. Solanaceae alkaloids have significant effects on the horse's nervous system and gastrointestinal tract. Ingestion of nightshade plants--fresh or dried form, often causes variable signs of colic within a couple hours of eating the plant. Possible symptoms after horses ingest nightshade include acute hemorrhage, gastroenteritis, weakness, excess salivation, dyspnea, trembling, progressive paralysis, prostration, and death. Toxicity is highest in green berries, followed by red or black berries, leaves, stems and roots. It is estimated that 1 to 10 pounds of ingested plant material is fatal to horses.

Most horses will not eat nightshade plants unless they are very hungry with no other feed source present. It can however often be found in baled hay, which increases the chances of horses consuming it. Nightshades are still toxic, even in dried form. Nitrates can also accumulate in the plant material.

What Nightshades Look Like

The flowers are five-lobed and are white or purple flowers which form fleshy green berries or fruits which turn yellow or black once matured. The leaves or alternate or opposite, hairy or smooth, and some have prominent spines. Nightshade species that have been implicated as a cause of previous poisoning incidents in horses include:
  • Black nightshade (Solanum nigrum)
  • Bittersweet nightshade (Solanum dulcamara)
  • Silver-leaf nightshade (Solanum elaeagnifolium)
  • Tropical soda apple (Solanum viarum Dunal)
  • Common or American nightshade (Solanum americanum)
  • Horse or bull nettle, Carolina horsenettle (Solanum carolinense)
  • Hairy nightshade (Solanum physalifolium)
  • Jimsonweed (Datura spp.)
  • Green tomato and potato vines (Lycopericon esculenium)
  • Day Jessamine (Cestrum diurnum)


  • Abdominal Pain
  • Diarrhea
  • Dilated Pupils
  • Loss Of Appetite
  • Loss Of Muscular Coordination
  • Apparent Hallucinations
  • Convulsions
  • Sudden Depression


CHEMICAL CONTROL: Metsulfuron methyl (Cimarron®) at 0.1 to 1 oz plus either 2,4-D or dicamba (Banvel®, Clarity®, Oracle®, Sterling®). Can be suppressed or controlled if triclopyr + 2,4-D (Crossbow®) is applied at 4 qts/A or applied with a handheld, high-volume applicator at 1.5% v/v mix with water.

MECHANICAL CONTROL: Can be hand-pulled but requires the removal of all stems to prevent resprouting.