Please read this text about the liver. Tylenol is NOT without its own problems and too much can cause respiratory arrest. If you drink any alcohol and take Tylenol, you are in major danger of damaging your liver. It is resilient but can only recover to a point. This said, let me address your question further:
It is hard to compare Tylenol and aspirin as they do not function the same way. Aspirin is an anti-inflammatory and a fever reducer. It can save someone having a heart attack. However, it can also damage the stomach and cause excess bleeding if abused, or taken by someone too sensitive to it. Tylenol may help a headache but it is not an anti-inflammatory so in the opinion of this severe arthritic woman, it is useless for back ache caused by arthritis, or any other bony or muscle complaint. It also is not a fever reducer.
However, in a child with the flu, or chickenpox, you cannot administer aspirin or the child could develop Reye syndrome and become extremely ill and die.
For me and my bone pain and muscle aches, I will stick to aspirin or ibuprofen. I have tried Tylenol in all its strengths and get no relief from it at all. I even used to work for the company that makes it and loved working there, but it just cannot do what aspirin can. However, it is all some people have when they cannot take aspirin or any other non-steroidal anti-inflammatory.
All medication should be used cautiously and judiciously. It is important that your pharmacist or physician know every single thing you take, from prescribed to over the counter, before you put another medication into your body. Side-effects from mixing the wrong medications can be lethal and liver transplants are very expensive.
Please see entire article below as it is very informative.
Your liver: An owner's guide
Special to CNN.com
The liver is one of your body's largest and most important organs. Located just under your rib cage on the right side of your abdomen, it's about the size of a football, weighs 3 to 4 pounds and performs more than 500 vital functions. Without it, you couldn't absorb food, remove toxic substances from your body or stay alive.
Your liver is incredibly resilient. It can remain functional after losing 80 percent to 90 percent of its cells to disease. It can completely regenerate itself in a few weeks even if much of it has been removed during surgery.
But it's not indestructible. Toxins such as alcohol and drugs, and viruses such as hepatitis B and C can cause permanent liver damage. With advanced liver disease (cirrhosis), healthy liver tissue is replaced with scar tissue and your liver is no longer able to repair itself, gradually losing function and eventually failing. Although early-stage liver disease is more treatable now than in the past, cirrhosis is usually only curable with a liver transplant.
Your liver: A brief anatomy lesson
A healthy liver is cone-shaped, with a smooth, rubbery texture. Its color is dark reddish-brown because at any given moment it holds a pint of blood. It's divided into lobes: a large right lobe and smaller left lobe that tapers toward a tip. Unlike most other organs in your body, your liver has a dual blood supply. Most of its blood comes from the portal vein, which carries nutrients and toxins from your digestive system. The rest comes from the hepatic artery, which supplies oxygen-rich blood from your heart.
Everything you eat, drink, breathe and absorb through your skin eventually reaches your liver. Its 300 billion cells control a process called metabolism, in which your liver breaks down nutrients into usable byproducts. These byproducts are delivered to the rest of your body by your bloodstream. Your liver also metabolizes toxins into byproducts that can be safely eliminated. Some of these byproducts are routed into your bloodstream and carried to your kidneys, which filter them so that they can be excreted in urine. Others are carried away by bile, a yellow or greenish fluid produced by your liver. These byproducts flow through bile ducts to your gallbladder and intestines so that they can be excreted in feces.
What your liver does
Although separating nutrients from waste is one of your liver's most important functions, it's not the only one. Your liver is also a storage depot for sugar (glucose), which is released when you need energy. And it's a chemical factory, producing many substances that perform vital tasks in your body. Some substances produced by the liver include:
Albumin, a protein that regulates the exchange of water between blood and tissues
Bile, a fluid that carries away waste and digests fat in the small intestine
Cholesterol, a substance needed by every cell in the body
Clotting factors, which help stop bleeding
Globin, part of the oxygen-carrying hemoglobin in blood
Immune factors, which protect against infection
How to protect your liver
Excessive alcohol consumption over many years is the leading cause of liver disease. Too much alcohol can make a normal liver swell with fat, causing a condition called fatty liver. If the fat becomes inflamed, it can lead to either alcoholic hepatitis, which causes serious but often reversible liver damage, or cirrhosis, which causes irreversible liver damage. Because of extensive scarring, a cirrhotic liver shrinks to a fraction of its former size.
Here are the most important things you can do to protect your liver:
Drink alcohol in moderation, if at all. Over many years, more than one drink a day for women and more than two drinks a day for men may be enough to lead to cirrhosis. Illegal drugs, especially cocaine, also can cause liver disease.
Don't mix other drugs with alcohol. Acetaminophen (Tylenol, others) can be toxic to the liver even if you drink in moderation.
Get vaccinated against hepatitis B. If you're at increased risk of contracting hepatitis or if you've already been infected with any form of the hepatitis virus, talk to your doctor about getting the hepatitis B vaccine.
Use medications wisely. Only use prescription and nonprescription drugs when you need them and take only the recommended doses. Talk to your doctor before mixing herbs or prescription or nonprescription drugs.
Beware of certain supplements. Herbal supplements that can be toxic to the liver include kava, comfrey, chaparral, jin bu huan, kombucha tea, pennyroyal and skullcap. Also avoid high doses of vitamins A, D, E and K.
Avoid contact with other people's blood and body fluids. Hepatitis viruses can be spread by accidental needle sticks, improper cleanup of blood or body fluids and sharing intravenous needles. It's also possible to become infected by sharing razor blades or toothbrushes or by having unsafe sex.
Be careful with aerosol sprays. When you use an aerosol cleaner, make sure the room is ventilated, or wear a mask. Take similar protective measures when spraying insecticides, fungicides, paint and other toxic chemicals.
Watch what gets on your skin. When using insecticides and other toxic chemicals, cover your skin with gloves, long sleeves, a hat and a mask.
Don't eat too many fatty foods. Your liver makes all the cholesterol your body needs. Eating a well-balanced, nourishing diet will help your liver do its job properly. A regular exercise program will help keep your liver healthy, too.
Watch your weight. Even if you don't drink alcohol, obesity can cause a condition called nonalcoholic fatty liver disease, which may include fatty liver, hepatitis and cirrhosis.
See your doctor if you develop any signs or symptoms of liver disease. These include yellow discoloration of the skin or eyes, abdominal swelling or severe abdominal pain, prolonged itching of the skin, very dark urine or pale stools, the passage of bloody or tar-like stools, chronic fatigue, nausea and loss of appetite.