Procter & Gamble was responding to reports from a paediatrician in Wales that a four-year-old he had seen, who had been drinking 1.5 litres of the drink a day, was a "yellowy colour". Dr Duncan Cameron, from Glan Clywd Hospital, near Rhyl, Clywd, had the child brought to him after her hands and face turned bright orange and yellow. Analysis revealed that her condition was caused by betacarotene, an additive that boosts the drink's orange colour and vitamin A content.
Dr Cameron now intends to warn other doctors, with letters to medical journals.
A spokeswoman for Procter and Gamble said the doctor had not contacted them directly but she said the child had been drinking "too much" and would have suffered the same effects with carrot juice. She said there were no safety risks and people affected returned to a normal colour in a few weeks.
Every 100ml of Sunny Delight contains a small quantity - 120 micrograms - of beta carotene, about 15 per cent of the recommended daily intake for an adult. A child's body would not be able to cope with beta carotene levels in 1.5 litres of the drink - it would represent more than twice the recommended daily adult intake.
The spokeswoman added: "The child apparently drank 1.5 litres per day. That would be more than the total daily fluid intake of a child of that age and you would expect a mix of different drinks, not just one type.
"This is excessive consumption and consumption on that scale would lead to a yellowing of the skin because of the beta carotene, in the same way as drinking too much carrot juice or orange juice would.
"The tanning tablets we use before going on holiday is beta carotene and works in much the same way.
"The condition is harmless, there is no health risk and skin will return to normal in a few weeks."
The incident has been reported as television advertising for the product shows snowmen turning yellow after raiding a fridge for Sunny Delight.