Arsenal Players were hit by food poisoning in China that stop some of their big players from playing their pre-season friendly match against Bayern Munich on Wednesday 19th July, 2017, manager Arsene Wenger said in a statement.
Wenger said the sickness really affect the Arsenal camp, combined with the severe heat in China and extensive traveling to different climates wasn't "ideal humanly" for the players.
Olivier Giroud didn't play the Wednesday's friendly victory against the Germany giant Bayern Munich because of the incident, then captain Per Mertesacker were substituted just moments before kick-off because he too fell ill with the same problem.
Arsenal's latest signee Sead Kolasinac also had to come off before the break and second-half substitutes. Walcott and Aaron Ramsey both ended the match not feeling well.
During the match, the Arsenal team were poor in the first 36 degrees Celsius (97F) heat and Wenger concluded that the extreme conditions in Shanghai were "a shock" after flying from Australia, which is in winter.
"I was a bit scared that tonight we could have big problems and in fact in the first-half we suffered a bit," said the coach.
"Ramsey finished the game, but Walcott, Kolasinac, Mertesacker, Giroud, they all had a little food poisoning."
According to the French coach, the club did not know what caused the food poisoning.
Wenger added of the punishing pre-season schedule that many top European clubs now undertake too far flung destinations for commercial reasons; "If you ask me is it ideal physically to prepare? I'd say certainly not.
" Has it got other advantages? Yes because we can meet fans all over the world so that is very positive."