does it produce any toxic substances?
Yes, bufotoxin.
Common toad
The main toxic substance found in the parotoid gland and skin of the common toad is called bufotoxin. 
what is the name of a small toad The common toad. how big can this get? It reaches maturity at three to seven years old but there is great variability between populations. how does it behave under threat? When attacked, it adopts a characteristic stance, inflating its body and standing with its hindquarters raised and its head lowered.
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Common toad [SEP] Bufotoxin
The main toxic substance found in the parotoid gland and skin of the common toad is called bufotoxin. It was first isolated by Heinrich Wieland and his colleagues in 1922 and they succeeded in identifying its structure about 20 years later. Meanwhile, other workers succeeded in isolating the same compound and its parent steroid bufotalin from the Japanese toad ("Bufo japonicus"). By 1986, researchers at the Arizona State University had succeeded in synthesizing the toad venom constituents bufotalin, bufalitoxin and bufotoxin. The chemical formula of bufotoxin is CHNO. Its physical effects resemble those of digitalis which in small doses increases the strength with which the heart muscle contracts and which is used in the treatment of congestive heart failure.