Green’s Dictionary of Slang

(Aus.) an amphetamine.

1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xliii 11/3: yippee beans: Methadrine, dexadrine and other stimulant pills.
1971		R.N. Cassel Drug abuse education 34: Amphetamines [...] ‘jolly-beans’ (or ‘yippee beans’).
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 53: Yippee Beans Amphetamines.
1995		C.K. Long Undefended Borders 62: And, no, that doesn't mean I’m into the yippee beans again — not that you could buy anything here anyway.
1998		P. Doyle (con. late 1950s) Amaze Your Friends (2019) 65: O’Keefe [...] grinding his teeth, half mad on yippee beans.
2007		A. Fraser Court in the Middle n.p.: The yippee beans were deadening my faculties.