Madonna said she is on the "road to recovery" as she issued a thank you message for the "positive energy, prayers and words of healing and encouragement".
The singer, 64, was forced to postpone several upcoming tour dates after spending several days in intensive care last month. The US pop superstar developed a "serious bacterial infection", her management said in a statement.
In her first Instagram post since the news broke, she wrote: "Thank you for your positive energy, Prayers and words of healing and encouragement. I have felt your love. I'm on the road to recovery and incredibly grateful for all the blessings in my life.
"My first thought when I woke up in the hospital was my children. My second thought was that I did not want to disappoint anyone who bought tickets for my tour. I also didn't want to let down the people who worked tirelessly with me over the last few months to create my show. I hate to disappoint anyone.
"My focus now is my health and getting stronger and I assure you, I'll be back with you as soon as I can! The current plan is to reschedule the North American leg of the tour and to begin in October in Europe."
She ended her post writing: "I couldn't be more grateful for your care and support. Love, M".
The singer had been about to embark on her Celebration Tour of North America and Europe, due to kick off in Canada in July.
