Spokeswoman Carolina Satterwall says Hetfield caught a stomach bug Sunday and suffered dehydration but left the hospital that evening. He has returned to the United States with the rest of the band.
The fans found out about the cancellation minutes before the concert was due to start, when the other members came onstage to deliver the news.
Drummer Lars Ulrich said the band members were "truly, truly, truly sorry."
"Trust me, none of you guys wanna hear me, Rob or Kirk sing," he added, referring to bassist Robert Trujillo and lead guitarist Kirk Hammett.
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