Green’s Dictionary of Slang

1. a purgative, a medicine; thus v. jollop, to lace with a purgative (see cite 1914).

1672		M. Atkins Cataplus 10: She lookt o’th’ sudden pale as ashes, / [...] / As if she had taken a full cup Of Chymick potion, or jallop.
c.1785		‘Darby O’Gallagher’ in A. Carpenter Verse in Eng. in 18C Ireland (1998) 400: His excellent musick is good for the tisick, / It works the fair maids like a dose of jallip.
1850		Cambridge Indep. Press 12 Jan. 4/8: Perfumery and jollop snuff and ginger.
1891		Blackburn Standard 30 May 2/6: Jollop (jalap). Yo’ need no knocker-up, or ’larum, to ged yo’ up soon i’ th’ mornin’ after tekkin’ a penn’orth o’ this fine owd summer beverage.
1899		Boy’s Own Paper 4 Mar. 356: ‘Old Sniff would keep on spinning yarns about what his mother used to do, and give him salts and senny once a week.’ ‘Yah! Don’t you believe him, sir,’ cried Sniff; ‘it was him, and about jollop too.’.
1904		Pall Mall Gaz. 24 Sept. 9/1: Would Mrs. Smale see to it that the Boy got a Cooling Doase. Wich she did the old Cat, with Jollup overnite and Epsum Salts in the Morning.
1914		in L. Macdonald Voices & Images of Great War (1991) 30: Our early morning tea was ‘jolloped’.
1915		Sport (Adelaide) 26 Feb. 5/4: They really made the public think / They had a dose of jollop.
1931		Tamworth Herald 1 Aug. 7/3: He also drank 40,000 bottles of medicine and immense quantities of jalep (or jollop).
1955		D. Niland Shiralee 146: He nutted out some jollop for her cough.
1965		G. Melly Owning Up (1974) 233: It [i.e. a drink] had been well-laced with ‘Jollops’, a very strong laxative which [...] worked instantly.
1990		‘Miss Read’ Friends at Thrush Green 229: The doctor was not the only one to supply jollop.
2002		R.C. Lilley An A-Z of Management for Healthcare Professionals 93: [...] jab our youngsters with a cocktail of immunisation jollop.

2. strong liquor or a measure of liquor.

1955

N. Pulliam I Travelled a Lonely Land (1957) 235/1: jollop – strong whisky, sometimes a laxative.