Blackcurrant can damage both unopened and open flowers when the temperature falls below . The flowers at the base of the strig are more protected by the foliage and are less likely to be damaged. In midsummer the strigs of green fruit ripen to edible berries, very dark purple in colour, almost black, with glossy skins and persistent calyxes at the apex, each containing many seeds. An established bush can produce about 4.5 kilograms (10 pounds) of fruit each year. Plants from Northern Asia are sometimes distinguished as a separate variety, "Ribes nigrum" var. "sibiricum", of which "Ribes cyathiforme" is considered
Solanum nigrum species. Some of the major species within the "S. nigrum" complex are: "S. nigrum", "S. americanum", "S. douglasii", "S. opacum", "S. ptychanthum", "S.retroflexum", "S. sarrachoides", "S. scabrum", and "S. villosum". Solanine levels in "S. nigrum" can be toxic. Children have died from poisoning after eating unripe berries. However, the plant is rarely fatal, with ripe berries causing symptoms of mild abdominal pains, vomiting, and diarrhea. Poisoning symptoms are typically delayed for 6 to 12 hours after ingestion. Initial symptoms of toxicity include fever, sweating, vomiting, abdominal pain, diarrhea, confusion, and drowsiness. Death from ingesting large amounts of the plant results