عن عبد الله بن عمرو رضي الله عنهما قال: قال رسول الله صلى الله عليه وسلم: «مَنْ تَطَبَّبَ، ولا يُعْلَمُ مِنْهُ طِبٌّ، فهو ضامِنٌ»  
[حسن] - [رواه أبوداود والنسائي وابن ماجه]

Abdullah Ibn Amr (RA) narrates that the Prophet of Allah ﷺ said: "Whoever claims to be a doctor, whilst not having attained the knowledge (and training) to be regarded as being proficient in medicine, are responsible (for the harm they may cause)

This is a famous authentic hadeeth in the books of Abu Dawud and Ibn Majah which sounds a warning for many today who practice without gaining proper knowledge and training in the field. This particular hadeeth is narrated in respect of the Islamic rulings regarding diyyat and compensation for when a life or limb is taken. In the western medical field the issue of medical malpractice is commonly known and in many countries doctors are required to have insurance for this very purpose as the practice of being sued and taken to tasks for medical mistakes is very common.

Unfortunately there is a misconception amongst those who practice what they regard as "sunnah remedies" and have undergone very short or minimal training in them, that any harm that arises is not their fault. They often attribute it to "taqdeer' shifting the blame away from them. This is completely incorrect as evidenced by the hadeeth.

The fact is that all remedies and therapies have to be prescribed based on knowledge and proper training. There are contraindications for any remedy, whether is a remedy found in the sunnah or not. Hijama cannot be prescribed for every person and at any time, there are rules surrounding its use which those who have studied in detail know and understand. There are also ahadeeth that prohibit doing Hijama on certain days and in certain conditions. While some of these are regarded as weak, they are to the level that they should be practiced upon for the sake of caution especially since they correspond with the illat, the reason of prohibition from other ahadeeth and from the medical understanding.

There are also time when other remedies are not suitable, for example Nabi ﷺ stopped sahaba from eating dates while they were suffering from a particular illness.

In order for a person to practice medicine they should have knowledge in training at the minimum in the following fields:

1. Anatomy and Physiology: A practitioner should have a good understanding of the human body and how it works. This includes knowledge of the different systems of the body, their functions, and how they are interrelated. Without a good understanding of anatomy and physiology, a practitioner of hijama may inadvertently apply cups to areas that could be harmful to the patient. For example, applying cups over the carotid artery in the neck could cause injury or even death.
2. Pathology: Knowledge of common diseases and disorders, their causes, symptoms, and treatments is essential for any healing modality. If a practitioner is not familiar with common diseases and disorders, their causes, symptoms, and treatments, they may not be able to properly diagnose and treat a patient. For example, if a patient presents with symptoms of heatstroke but the practitioner is not familiar with the disease, they may not be able to properly advise the patient or refer them to a medical doctor for proper treatment.
3. Diagnostic Skills: A practitioner should be able to assess a patient's condition and develop a treatment plan based on their assessment. This requires skills such as palpation, observation, and listening. If a practitioner is not skilled in assessment techniques such as palpation, observation, and listening, they may not be able to accurately assess a patient's condition. For example, if a patient presents with stomach pain but the practitioner is not skilled in palpation, they may not be able to accurately locate the source of the pain or identify a potentially life threatening situation. There are several life-threatening conditions that can present with stomach pain, and failure to diagnose them correctly can have serious consequences. One example is an abdominal aortic aneurysm (AAA), which is a bulging or swelling in the wall of the aorta, the main blood vessel that supplies blood to the abdomen, pelvis, and legs. An AAA can cause abdominal pain, which may be severe and sudden in onset. Other symptoms may include back pain, nausea, vomiting, and dizziness. If an AAA ruptures, it can cause massive internal bleeding, which can be life-threatening. If a practitioner is not able to correctly diagnose an AAA, they may not refer the patient for urgent medical intervention, which can result in a delay in treatment and potentially fatal consequences. Therefore, it is important for a practitioner to have diagnostic skills and be able to recognize the signs and symptoms of potentially life-threatening conditions like AAA.
4. Treatment Techniques: A practitioner should have knowledge and proficiency in the specific treatment techniques of their modality. This may include techniques such as hijama, acupuncture, or herbal remedies. For example, if a hijama practitioner does not know how to properly apply the cups, they may not be able to create the desired suction and the treatment may not be effective or they may remove too much blood from a patient too frequently resulting in severe anemia which can have serious complications.
5. Pharmacology: A practitioner should have a basic understanding of pharmacology, which is the study of how drugs affect the body. This includes knowledge of how drugs are absorbed, metabolized, and eliminated by the body, as well as their potential side effects. If a practitioner does not have a basic understanding of pharmacology, they may not be able to properly advise patients on the use of prescription drugs, or properly manage potential side effects. For example, if a patient is taking blood thinners and the practitioner does not understand how these drugs work, they may inadvertently cause bleeding during the hijama treatment.
6. Herbal Medicine: A practitioner should have a good understanding of the herbs and other natural remedies used in their modality. This includes knowledge of their properties, uses, and potential side effects.
7. Drug-Herb Interactions: A practitioner should be aware of potential interactions between herbs and other natural remedies and prescription drugs. These interactions can be beneficial or harmful, and can vary depending on the specific herbs and drugs involved. St. John's Wort is a popular herb used for depression, anxiety, and other mood disorders. However, it can interact with certain medications such as antidepressants, birth control pills, and blood thinners. A practitioner should be aware of these interactions and avoid using St. John's Wort with patients who are taking these medications. Ginseng is another popular herb used for its energy-boosting and stress-relieving properties. However, it can interact with blood thinners and some diabetes medications, increasing the risk of bleeding and hypoglycemia. A practitioner should be aware of these interactions and avoid using ginseng with patients who are taking these medications. Licorice root is a popular herb used for digestive issues, but it should be avoided in patients with high blood pressure, as it can increase blood pressure levels. A practitioner should be aware of this contraindication and avoid using licorice root with patients who have high blood pressure. Chamomile is a popular herb used for its calming and sleep-inducing properties. However, high doses of chamomile can cause nausea and vomiting. A practitioner should be aware of proper dosages and preparations for chamomile and avoid using high doses with patients. Echinacea is a popular herb used for its immune-boosting properties. However, some people can experience allergic reactions to echinacea, including rashes, hives, and difficulty breathing. A practitioner should be able to recognize these adverse reactions and manage them appropriately. Like this there are many other herb interaction and adverse reactions that need to be known.
8. Contraindications: A practitioner should be aware of any contraindications or conditions that would make a particular herb or remedy unsafe for a particular patient. This may include conditions such as pregnancy, liver or kidney disease, or allergies. For example, if a patient is pregnant and the practitioner prescribes a high dose of a seemingly safe herb such as cinnamon that is contraindicated during the third trimester pregnancy, the patient and the baby could be at risk.
9. Dosages and Preparations: A practitioner should have knowledge of proper dosages and preparations for herbs and natural remedies. This includes knowledge of how to prepare herbs for use, as well as how to administer them safely and effectively.
10. Adverse Reactions: A practitioner should be able to recognize and manage adverse reactions to herbs and natural remedies. This may include symptoms such as allergic reactions, digestive upset, or other adverse effects.

A Muslim practitioner should also have knowledge of the verses of Quran and the Ahadeeth that relate to the aqeeda and fiqh of practicing medicine so that they know how to approach illness and the sick correctly and advise them in the appropriate way about their illness and also what treatments and methods would be permissible and which would not be suitable.

A practitioner should also be familiar with the temperament (mizaaj) of a patient as well as the time of the month, the season, the climate and other factors which can impact and influence people's condition and treatment.