The Regnellian herbarium holds material from South- and Central America and the Caribbean, at present about 400.000 specimens. The type material comprises of some 25.000 specimens, a part of which has been computerized and made available in a database, botanical type collection. A separate Ecuador herbarium has about 35.000 specimens, and the historical Swartz herbarium another 6.000 specimens. The Regnellian herbarium includes scientifically important material collected by e. g. E. L. Ekman, G. A. Malme and E. Asplund.

Thanks to the physician and botanist Anders Fredrik Regnell, the Regnellian herbarium is today one of the largest collections of South American plants. More than 20 Swedish expeditions to South America have taken place over the years, the first in 1892-1894, led by C. A. M. Lindman and G. A. Malme. The Regnellian expeditions in combination with an active exchange with other institutions, mean that the Regnellian herbarium is continually growing.