A paregoric is a medicine; specifically and figuratively, something that soothes.
The origin of this odd word is the Greek paregorikos for soothing or encouraging words (from paregorein, to speak soothingly to). This derives from para, beside, and agora, literally the market place, but also a place of assembly (the related agoreuein meant to speak in public).
The word moved into late Latin in the sense of something soothing or consoling; at one time it was used for any medicine that had that effect. Later it was applied specifically to a tincture (a solution in alcohol) of opium flavoured with camphor, aniseed and benzoic acid. It was a flavoured — and usually less potent — form of laudanum, a simple tincture of opium. It was used as a medicine to treat diarrhoea and coughing, especially in children.
The only clues Anthea has been able to glean about her origins was that she was clean and well cared for. “In fact, the farmer’s wife smelled my hair, which was freshly washed, and they also noticed that my breath smelled of paregoric, a sedative commonly used then to ease teething pain.” This may be a sign that she had, right up until her abandonment, been well looked after.
Daily Mail, 29 May 2006. The incident described here took place in the 1930s.
At least one of my British dictionaries marks it as historical only, and the word seems no longer to be familiar to our pharmacists (they call it camphorated opium tincture instead); but it is, for example, still in the US pharmacopoeia under that name.