Popular drinks brands Ribena and Lucozade have been put up for sale in a move which could net GlaxoSmithKline more than £1 billion.
The drugs giant confirmed it is selling the soft drinks brands after concluding they would grow faster under a new owner.
Confirmation of the sale came as London-based Glaxo reported a 12% slide in core pre-tax profits to £1.8 billion in the first three months of the year, and a 3% fall in sales to £6.5 billion.
Glaxo is battling tough markets in Europe where austerity drives have hit medicine prices and affected the development of new drugs across the continent. It also faces fierce competition from generic drugs. The group is restructuring its European pharmaceuticals operations to save £1 billion by 2016.
Ribena and Lucozade are largely sold in Western markets and earn sales of about £600 million a year. They are made in the UK at a factory in Coleford, Gloucestershire, and are also produced in Nigeria and Kenya.
Lucozade and Ribena, which were owned by Beecham prior to its merger with SmithKline, date back to 1927 and the 1930s respectively.
Glaxo chief executive Sir Andrew Witty said it will sell the brands if it can recoup "appropriate value". He did not confirm a price tag but analysts believe they could be worth more than £1 billion.
The company has already had interest in the brands since announcing the review in February.
He said: "We concluded that the tremendous growth potential of these iconic brands, particularly outside the core Western markets, could be better leveraged by companies with existing category presence and infrastructure in these regions."
Possible bidders are said to include Japan's Suntory Holdings, which owns Orangina Schweppes, as well as a host of private equity firms. Suntory could not be reached for comment.
The Sunday Times rich list 2013
GSK to sell Ribena and Lucozade
The 59-year-old billionaire has an almost 30% stake in Arsenal Football club and tops the list with an estimated worth of £13.3 billion.
Blavatnik's wealth rose from £3.4 billion last year to £11 billion in 2013 making him the biggest climber. He owns Warner Music and received £2 billion in April for his stake in TNK-BP.
Indian tycoons Sri and his brother Gopi Hinduja have a wealth of £10.6 billion from the industry and finance sector. The brothers made their fortune from their family firm Hinduja Group, a textile and trading exporter founded by their father in 1914.
Mittal spent eight years at the top of the rich list but slipped down to fourth place this year when the 40% stake he holds with his wife Usha in steelmaking giant ArcelorMittal plummeted from £28 billion to £5.95 billion.
With wealth totalling £9.3 billion, Roman Abramovich is most famous for buying Chelsea FC. A £200 million drop in his fortune lowers Abramovich from third to fourth spot.
Although largely unknown in Britain, 68-year-old Fredriksen is notorious in his native Norway as owner of the world's largest fleet of oil tankers. Once Norway's richest man and now a Cypriot national, the high-school dropout's companies are major players in shipping, offshore drilling and seafood.
The British-born billionaires, the Reuben brothers, are best-known for their vast UK property empire, which includes the John Lewis Partnership's headquarters in London's Victoria.
The Duke of Westminster is the second-highest ranked British billionaire and is worth an estimated £7.8 billion. He owns property group Grosvenor Estates, and half of London's Mayfair and Belgravia, as well as vast portions of the UK and Scotland.
With no change to their wealth this year, the Bertarellis are worth £7.4 billion. Born Kirsty Roper in 1971 into the Churchill China dynasty, 41-year-old Kirsty was a model and wrote the All Saints worldwide hit 'Black Coffee'.
Charlene de Carvalho-Heineken inherited a huge stake in Heineken, the world's third-largest brewer on the death of her father Freddy Heineken in 2002. Michel is an investment banker, former Olympic skier and toboganner, and and actor who appeared in the desert epic 'Lawrence of Arabia.'