The American tries to keep a clear head going into all her finals.
The 19-year-old says she was given ibuprofen and therefore did not have to apply for a Therapeutic Use Exemption.
Simone Biles has now won 13 career gold medals.
Artur Dalaloyan beat Xiao Ruoteng on a tie-break to become the new world champion.
Nassar was sentenced in February to up to 125 years in prison after some 200 women, including Olympians, testified about decades of abuse at his hands.
Biles finished a provisional first place in the vault, beam and floor competitions.
As well as medals, Doha will be the first opportunity for competitors to qualify for the 2020 Olympics.
Simone Biles was displeased by a Nike-related tweet made by new USA Gymnastics president Mary Bono.
The president and CEO of US Gymnastics's reported departure comes after a tumultuous week which saw senior coach Mary Lee Tracy ousted 3 days after her appointment.
Simone Biles returned from an almost two-year hiatus in style, beating Morgan Hurd by 6.55 points.
The creation of a Gymnastics Ethics Foundation will be put to a vote of the body's national member federations at the next congress, to be held in Baku in December.
141 survivors received the Arthur Ashe Award for Courage.
Nassar pleaded guilty to sexually assaulting women and girls over a two-decade period under the guise of medical treatment.
The Michigan University has agreed on a 500 million settlement with victims of sexual abuse of former US gymnastics doctor Larry Nassar.
Former star athletes who were sexually abused by one-time sports doctor Larry Nassar condemned an "epidemic" of pedophilia in the United States, calling for a "nationwide sweep" and greater accountability.
Olympic gold medalist McKayla Maroney revealed sexual abuse by Larry Nassar five years before his arrest but nobody listened, she told NBC News' "Dateline" in an interview aired on Sunday.
A gymnastics coach in the US state of Wisconsin is facing child pornography charges for secretly recording athletes at his training center locker room and bathroom, police announced Thursday.
Many welcomed the overdue resignation, citing Nassar's years of abuse.
The probe will centre on whether Michigan State met requirements under a federal law that bars sexual discrimination in schools that receive federal funding.
Olympic gold medalist Aly Raisman says women do not have to be modest to be respected
The scandal sparked various investigations into why the U.S. Olympic Committee, sport governing body USA Gymnastics, and Michigan State University failed to investigate these complaints.
Failure of the board of directors to resign by next week would lead to 'immediate termination proceedings'.
USA Gymnastics has allowed McKayla Maroney to speak freely about her sexual abuse case, having been sued by the gymnast last month.
Gabby Douglas, an Olympic gold medal-winning gymnast, has accused Larry Nassar, former USA Gymnastics team physician, of sexual abuse.
12Page 1 of 2