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 from cardiac arrhythmias and respiratory failure. Livestock have also been poisoned from nitrate toxicity by grazing the leaves of "S. nigrum". All kinds of animals can be poisoned after ingesting nightshade, including cattle, sheep, poultry, and swine. However, in central Spain, the great bustard ("Otis tarda") may act as a seed disperser of European black nightshade ("Solanum nigrum"). Black nightshade is highly variable, and poisonous plant experts advise to avoid eating the berries unless they are a known edible strain. The toxin levels may also be affected by the plant's growing conditions. The toxins in "S. nigrum" are most concentrated