Editor's Note: The initial article published here described a report from the Boston Globe on Steven Tyler's health. As that Boston Globe article has been changed and the information is no longer displayed, we have revised accordingly.
Update (10/18/17): Below is Steven Tyler's official statement on September 30th, in response to prior reports about his health issue.
"It breaks my heart to have left this tour early...The band has never played better...Just watch the 100,000 people at Rock in Rio...I give you all an A+ for creative speculations but I certainly did not have a heart attack or seizure (unless Joe Perry is takin' a rippin' lead)...Sorry to have cut the tour short but I had to have a procedure that only my doc in the States could perform...We've been to Tel Aviv...to Russia...to Rio...and all the in-between...I guess it's true what they say...'That life's a pisser when eu're a peein'."
See earlier reporting below (09/28/2017):
Tyler himself has not acknowledged what exactly happened this week, although he did confirm that four upcoming shows would be cancelled due to a medical issue he described as "not life-threatening."
"To everybody in South America ... I'm very sorry and feel like I've let you down," Tyler said in a statement. "I flew back to the U.S. on doctor's orders last night after the show in São Paulo. Please not to worry ... I am not in a life threatening condition, but I need to deal with this right away, and get some rest and medical care immediately in order to sustain and maintain my future performances."
The 69-year-old rocker continued, "I promise I'll be back. Unfortunately, health does not wait and it's something even I can't schedule around our shows. As they say, 'We humans make plans, and God laughs.' I love you all and will be back with you soon."
A statement from Aerosmith said Tyler is expected to make a full recovery and will soon be "back on his feet rocking the world."
The band has suffered a few health complications in recent years, including in 2016, when guitarist Joe Perry collapsed backstage due to dehydration and exhaustion.
Steven Tyler out and about in recent years
Steven Tyler out and about in recent years
ROME, ITALY - SEPTEMBER 10: Steven Tyler attends Celebrity Fight Night on September 10, 2017 in Rome, Italy. (Photo by Venturelli/WireImage)
ROME, ITALY - SEPTEMBER 08: Steven Tyler performs at the Andrea Bocelli show as part of the 2017 Celebrity Fight Night in Italy Benefiting The Andrea Bocelli Foundation and the Muhammad Ali Parkinson Center on September 8, 2017 in Rome, Italy. (Photo by Jonathan Leibson/Getty Images for Celebrity Fight Night)
ST PAUL, MN - JULY 16: Aimee Preston and Steven Tyler pose on the red carpet at the 2017 Starkey Hearing Foundation So the World May Hear Awards Gala at the Saint Paul RiverCentre on July 16, 2017 in St. Paul, Minnesota. (Photo by Adam Bettcher/Getty Images for Starkey Hearing Foundation)
ST PAUL, MN - JULY 16: Steven Tyler performs at the 2017 Starkey Hearing Foundation So the World May Hear Awards Gala at the Saint Paul RiverCentre on July 16, 2017 in St. Paul, Minnesota.
(Photo by Adam Bettcher/Getty Images for Starkey Hearing Foundation)
CASTLE DONINGTON, ENGLAND - JUNE 11: Steven Tyler of Aerosmith peforms during the last ever Aerosmith show in the UK headlining day 3 of Download Festival at Donington Park on June 11, 2017 near Castle Donington, England. (Photo by Ollie Millington/WireImage)
TOPSHOT - Steven Tyler of Aerosmith performs at the Royal Arena in Copenhagen, on June 5, 2017. / AFP PHOTO / Scanpix / Nils Meilvang / Denmark OUT (Photo credit should read NILS MEILVANG/AFP/Getty Images)
LONDON, ENGLAND - JUNE 10: Steven Tyler attends a celebration of the Stella McCartney AW17 collection and film launch at Ye Olde Mitre on June 10, 2017 in London, England. (Photo by David M Benett/Dave Benett/Getty Images for Stella McCartney)
BERLIN, GERMANY - MAY 28: Steven Tyler and Joe Perry (Aerosmith) during 'Mensch Gottschalk - Das bewegt Deutschland' TV Live Show from Berlin at Studio Berlin Adlershof on May 28, 2017 in Berlin, Germany. (Photo by Franziska Krug/Getty Images)
MOSCOW, RUSSIA - MAY 23: American rock band Aerosmith's lead singer Steven Tyler performs during a concert at the Olimpiysky Sports Complex on May 23, 2017 in Moscow, Russia. (Photo by Alexander Miridonov/Kommersant via Getty Images)
LOS ANGELES, CA - MAY 12: Steven Tyler is seen on May 12, 2017 in Los Angeles, CA. (Photo by Hollywood To You/Star Max/GC Images)
LOS ANGELES, CA - FEBRUARY 14: Steven Tyler is seen at LAX on February 14, 2017 in Los Angeles, California. (Photo by starzfly/Bauer-Griffin/GC Images)
NEW YORK, NY - DECEMBER 03: Steven Tyler (L) and Aimee Ann Preston attend The Hospitality Committee For United Nations Delegations, Inc. Ambassadors' Ball 2016 at Metropolitan Club on December 3, 2016 in New York City. (Photo by Rob Kim/Getty Images)
MEXICO CITY, MEXICO - OCTOBER 27: Singer Steven Tyler of Aerosmith performs onstage at Arena Ciudad de Mexico on October 27, 2016 in Mexico City, Mexico. (Photo by Victor Chavez/WireImage)
SAO PAULO, BRAZIL - OCTOBER 15: Steven Tyler member of the band Aerosmith performs live on stage at Allianz Parque on October 15, 2016 in Sao Paulo, Brazil. (Photo by Mauricio Santana/Getty Images)
DEL MAR, CA - SEPTEMBER 17: Aerosmith (L) Steven Tyler and Joe Perry performs at the 2016 KAABOO Del Mar at the Del Mar Fairgrounds on September 17, 2016 in Del Mar, California. (Photo by Christopher Victorio/WireImage for Kaaboo Del Mar via imageSPACE)
DEL MAR, CA - SEPTEMBER 17: Aerosmith (L-R) Joe Perry and Steven Tyler performs at the 2016 KAABOO Del Mar at the Del Mar Fairgrounds on September 17, 2016 in Del Mar, California. (Photo by Christopher Victorio/WireImage for Kaaboo Del Mar via imageSPACE)
LOS ANGELES, CA - SEPTEMBER 14: Steven Tyler is seen at LAX on September 14, 2016 in Los Angeles, California. (Photo by starzfly/Bauer-Griffin/GC Images)