Selenium is effective for preventing selenium deficiency.

Selenium might also help improve mood, general feelings of well-being, and quality of life in people with this condition.

Adding salt enriched with selenium to food can prevent Kashin-Beck disease in children.

Pregnant women with low levels of selenium in the blood might have a higher chance of developing pre-eclampsia.

Selenium is a mineral found in soil, water, and some foods. It is important for making many body processes work correctly.

High dosage of selenium dioxide may cause

• Muscle tenderness
• Tremor
• Lightheadedness
• Facial flushing
• Nausea
• Vomiting
• Loss of energy
• Nail changes
• Hair loss
• Irritability
• Garlic breath odor
• A metallic taste

Selenium is unsafe when taken by mouth in high doses or for a long time. 

Selenium is safe during pregnancy and breast-feeding when used short-term in amounts

Selenium is safe for children when taken by mouth appropriately.

selenium might make autoimmune disease worse by stimulating the activity of the disease. 

Blood levels of selenium can be low in people undergoing hemodialysis.

Taking selenium can worsen hypothyroidism especially in people with iodine deficiency.

Selenium might decrease the ability of sperm to move, which could reduce fertility.

Long-term use of selenium supplements might slightly increase the risk of skin cancer recurrence, but this is controversial.

Selenium might increase the risk of bleeding during and after surgery.

Vitamin C consists of a water-soluble vitamin known as vitamin C. Vitamin C is also known as L-ascorbic acid or ascorbate.  It occurs as a white or slightly yellow crystal or powder with a slightly acidic taste. On exposure to light, it gradually darkens. In the dry state, it is reasonably stable in air, but in solution, it rapidly oxidizes.

• Vitamin C helps in the growth and repair of tissues of bones, cartilage, tendons, skin, hair, muscles and many more.
• Along with that, it helps in wound healing and also enhances the absorption of iron in our body.
• Excess of free radicals can speed up the ageing process, vitamin C due to its rich antioxidant properties help to reduce the harmful effects of these free radicals. Vitamin C is very crucial for bone and teeth health.
• It improves vision and also regulates blood cholesterol levels.
• Owing to its numerous benefits, it is very important to take an adequate amount of vitamin C in your diet.

Possibly Effective for

• An eye disease that leads to vision loss in older adults (age-related macular degeneration or AMD).
• Irregular heartbeat (atrial fibrillation). Taking vitamin C before and for a few days after heart surgery helps prevent irregular heartbeat after heart surgery.
• Emptying the colon before a colonoscopy.
• Limb pain that usually occurs after an injury (complex regional pain syndrome). 
• Skin redness caused by injury or irritation (erythema). Using a skin cream containing vitamin C might decrease skin redness following laser resurfacing for scar and wrinkle removal.
• Airway infections caused by exercise. Using vitamin C before heavy physical exercise, such as a marathon, might prevent upper airway infections that can occur after heavy exercise.
• Swelling (inflammation) of the stomach (gastritis). Some medicine used to treat H. pylori infection can worsen stomach inflammation. Taking vitamin C along with one of these medicines called omeprazole might decrease this side effect.
• A condition in which red blood cells are broken down faster than they are made (hemolytic anemia). Taking vitamin C supplements might help manage anemia in people undergoing dialysis.
• High cholesterol. Taking vitamin C might reduce low-density lipoprotein cholesterol in people with high cholesterol.
• Lead poisoning. Consuming vitamin C in the diet seems to lower blood levels of lead.
• Osteoarthritis. Taking vitamin C from dietary sources or from calcium ascorbate supplements seems to prevent cartilage loss and worsening of symptoms in people with osteoarthritis.
• Pain after surgery. Taking 2 grams of vitamin C by mouth one hour before surgery might reduce pain and the need for opioid pain relievers after surgery. 
• Wrinkled skin. Skin creams containing vitamin C seem to improve the appearance of wrinkled skin. A vitamin C patch also seems to help reduce wrinkles.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using Vitamin C and call your doctor at once if you have:

• Joint pain, weakness or tired feeling, weight loss, stomach pain;
• Chills, fever, increased urge to urinate, painful or difficult urination; or
• Severe pain in your side or lower back, blood in your urine.

Common side effects may include:

• Heartburn, upset stomach; or

• Nausea, diarrhoea, stomach cramps.

• Transient mild soreness may occur at the site of intramuscular or subcutaneous injection.
• Too-rapid intravenous administration of the solution may cause temporary faintness or dizziness.
• Although vitamin C is generally considered safe, high doses can cause adverse effects, including heartburn, nausea, headaches, stomach cramps, and diarrhoea.
• Vitamin C is not stored in the body. If you take more than you need, the extra vitamin C will pass into your urine.
• Very large doses may also interfere with tests for sugar in diabetics and with tests for blood in the stool.

N-acetyl cysteine is most commonly used by mouth for cough and other lung conditions. It is also used for flu, dry eye, and many other conditions, but there is no good scientific evidence to support many of these uses.

N-acetyl cysteine comes from the amino acid L-cysteine. Amino acids are the building blocks of proteins. N-acetyl cysteine has many uses as medicine.

Major & minor side effects for Acetylcysteine

• Nausea and Vomiting
• Fever
• Runny Nose
• Diarrhea
• Abdominal pain
• Skin irritation and rahses
• Throat irritation
• Drowsiness
• Chest tightness
• Hives and wheezing
• Difficulty in breathing
• Presence of blood in cough
• Injection site pain
• Cool and moist skin
• Swelling and soreness of the inside of the mouth

This medicine is not recommended for use in pregnant and breastfeeding women unless clearly necessary. 

This medicine is not recommended for use in patients suffering from a severe and sudden attack of asthma. 

This medicine should not be used with topical antibiotics for relieving dry eye syndrome due to the increased risk of severe adverse reactions.

Both the oral and intravenous forms of this medicine are used for the treatment of paracetamol poisoning.

Use of this medicine may cause severe allergic reactions like a rapid fall in blood pressure, difficulty in breathing, rash, etc.