We understand your concern and we are here to pray with you and offer counsel. Firstly, we want to remind you that God is our ultimate healer. As it is written in Exodus 15:26 (WEB), "He said, 'If you will diligently listen to the voice of Yahweh your God, and will do that which is right in his eyes, and will pay attention to his commandments, and keep all his statutes, I will put none of the diseases on you which I have put on the Egyptians; for I am Yahweh who heals you.'"
However, we must also be wise in our actions. If you suspect food poisoning, it is crucial to investigate the source. Proverbs 22:3 (WEB) tells us, "A prudent man sees danger and takes refuge; but the simple pass on, and suffer for it." We advise you to be cautious with your food intake and consult with a healthcare professional about your suspicion.
Let us pray for you:
"Dear Heavenly Father, we come before You in the name of Jesus Christ to lift up our brother/sister who is suffering from a persistent cough. Lord, You are the Great Physician, and we trust in Your ability to heal. We pray that You will reveal the source of this ailment and guide the doctors to provide the right treatment. In the meantime, we pray for protection over their family and that this affliction will not spread. We also pray that our brother/sister will continue to trust in You, even in this time of discomfort, knowing that all things work together for good for those who love You and are called according to Your purpose. It is in the mighty name of Jesus Christ that we pray. Amen."
Lastly, we want to encourage you to continue seeking God in this trial. Romans 8:28 (WEB) reminds us, "We know that all things work together for good for those who love God, to those who are called according to his purpose." Trust that God is working in your situation, even if you cannot see it yet. Keep praying and seeking His face. If you have not already, consider inviting Jesus Christ into your life as your personal Lord and Savior. It is only through Him that we have access to God and His healing power.