Many things can affect how your body responds to a symptom and what kind of care you may need. These include:

• Your age. Babies and older adults tend to get sicker quicker.
• Your overall health. If you have a condition such as diabetes, HIV, cancer, or heart disease, you may need to pay closer attention to certain symptoms and seek care sooner.
• Medicines you take. Certain medicines, such as blood thinners (anticoagulants), medicines that suppress the immune system like steroids or chemotherapy, or natural health products can cause symptoms or make them worse.
• Recent health events, such as surgery or injury. These kinds of events can cause symptoms afterwards or make them more serious.
• Your health habits and lifestyle, such as eating and exercise habits, smoking, alcohol or drug use, sexual history, and travel.

If you're not sure if a fever is high, moderate, or mild, think about these issues:

With a high fever:

• You feel very hot.
• It is likely one of the highest fevers you've ever had. High fevers are not that common, especially in adults.

With a moderate fever:

• You feel warm or hot.
• You know you have a fever.

With a mild fever:

• You may feel a little warm.
• You think you might have a fever, but you're not sure.

Temperature varies a little depending on how you measure it. For adults and children age 12 and older, these are the ranges for high, moderate, and mild, according to how you took the temperature.

Oral (by mouth) temperature

• High: 40°C (104°F) and higher
• Moderate: 38°C (100.4°F) to 39.9°C (103.9°F)
• Mild: 37.9°C (100.3°F) and lower

A forehead (temporal) scanner is usually 0.3° C (0.5° F) to 0.6° C (1° F) lower than an oral temperature

Ear temperature

• High: 40.5°C (104.9°F) and higher
• Moderate: 38.5°C (101.3°F) to 40.4°C (104.7°F)
• Mild: 38.5°C (101.3°F) and lower

Armpit (axillary) temperature

• High: 39.8°C (103.6°F) and higher
• Moderate: 37.8°C (100°F) to 39.7°C (103.5°F)
• Mild: 37.7°C (99.9°F) and lower

Symptoms of serious illness may include:

• A severe headache.
• A stiff neck.
• Mental changes, such as feeling confused or much less alert.
• Extreme fatigue (to the point where it's hard for you to function).
• Shaking chills.

Certain health conditions and medicines weaken the immune system's ability to fight off infection and illness. Some examples in adults are:

• Diseases such as diabetes, cancer, heart disease, and HIV/AIDS.
• Long-term alcohol and drug problems.
• Steroid medicines, which may be used to treat a variety of conditions.
• Chemotherapy and radiation therapy for cancer.
• Other medicines used to treat autoimmune disease.
• Medicines taken after organ transplant.
• Not having a spleen.

• Severe diarrhea means having more than 10 loose, watery stools in a single day (24 hours).
• Moderate diarrhea means having more than a few but not more than 10 diarrhea stools in a day.
• Mild diarrhea means having a few diarrhea stools in a day.

You can get dehydrated when you lose a lot of fluids because of problems like vomiting or fever.

Symptoms of dehydration can range from mild to severe. For example:

• You may feel tired and edgy (mild dehydration), or you may feel weak, not alert, and not able to think clearly (severe dehydration).
• You may pass less urine than usual (mild dehydration), or you may not be passing urine at all (severe dehydration).

Severe dehydration means:

• Your mouth and eyes may be extremely dry.
• You may pass little or no urine for 12 or more hours.
• You may not feel alert or be able to think clearly.
• You may be too weak or dizzy to stand.
• You may pass out.

Moderate dehydration means:

• You may be a lot more thirsty than usual.
• Your mouth and eyes may be drier than usual.
• You may pass little or no urine for 8 or more hours.
• You may feel dizzy when you stand or sit up.

Mild dehydration means:

• You may be more thirsty than usual.
• You may pass less urine than usual.

Many prescription and non-prescription medicines can cause diarrhea. A few examples are:

• Antibiotics.
• Antidepressants.
• Antacids.
• Proton pump inhibitors, such as omeprazole (Prilosec) and lansoprazole (Prevacid).
• Medicines used to treat cancer (chemotherapy).

It is easy for your diabetes to become out of control when you are sick. Because of an illness:

• Your blood sugar may be too high or too low.
• You may not be able take your diabetes medicine (if you are vomiting or having trouble keeping food or fluids down).
• You may not know how to adjust the timing or dose of your diabetes medicine.
• You may not be eating enough or drinking enough fluids.

An illness plan for people with diabetes usually covers things like:

• How often to test blood sugar and what the target range is.
• Whether and how to adjust the dose and timing of insulin or other diabetes medicines.
• What to do if you have trouble keeping food or fluids down.
• When to call your doctor.

The plan is designed to help keep your diabetes in control even though you are sick. When you have diabetes, even a minor illness can cause problems.

Blood in the stool can come from anywhere in the digestive tract, such as the stomach or intestines. Depending on where the blood is coming from and how fast it is moving, it may be bright red, reddish brown, or black like tar.

A little bit of bright red blood on the stool or on the toilet paper is often caused by mild irritation of the rectum. For example, this can happen if you have to strain hard to pass a stool or if you have a hemorrhoid.

A large amount of blood in the stool may mean a more serious problem is present. For example, if there is a lot of blood in the stool, not just on the surface, you may need to call your doctor right away. If there are just a few drops on the stool or in the diaper, you may need to let your doctor know today to discuss your symptoms. Black stools may mean you have blood in the digestive tract that may need treatment right away, or may go away on its own.

Certain medicines and foods can affect the colour of stool. Diarrhea medicines (such as Pepto-Bismol) and iron tablets can make the stool black. Eating lots of beets may turn the stool red. Eating foods with black or dark blue food colouring can turn the stool black.

If you take aspirin or some other medicine (called a blood thinner) that prevents blood clots, it can cause some blood in your stools. If you take a blood thinner and have ongoing blood in your stools, call your doctor to discuss your symptoms.