Life Cycle - Plants (4B)
Post Lab 

  • Discussing medicinal uses of plants.
  • Analyzing components of drugs.


  • caffeine
  • drug
  • euphoric
  • excitant
  • hallucinogen
  • books on different drugs
  • Internet


Students research to find drugs derived from plants.


Plants range in size from 0.5 microns to 175 meters in length to hundreds of tons in weight. Rates of plant growth can vary from minutes to years. Plants are some of the most diverse and intriguing of all organisms on this planet. They are needed to keep us alive; they produce much of the oxygen in the atmosphere; they relieve pain and they cause much pain. This discussion of plants and their medicinal purposes can develop into a provocative discussion on drugs because a large amount of drugs or their synthetic derivatives come from plants.

The early interest in plants was probably due to use of plants materials for the treatment of human ills or for pleasure. Records show that plants played an important part in early western and eastern civilizations. Although today, chemists have been able to make synthetic drugs that mirror the effects of natural plants there are many plants that are still used. Belladonna, opium, psyllium, rhubarb, eucalyptus, licorice, nux vomica, and cinchona, are the sources of the important alkaloids, atropine, morphine, strychnine, and quinine respectively. Digitalis, a drug used for certain heart disorders, and used by many people, is derived from a plant. The most common drug obtained from plants is caffeine. Caffeine can be found in seeds (coffee, cocoa, cola), leaves (tea, mate (leaves from holly), yaupon, and bark (yoco). Historically caffeine has been used in most civilizations.

Drugs are usually taken because they give the user a feeling of euphoria. Euphoria is a feeling of general well-being. Hypnotics are drugs that cloud reasoning, consciousness, and though. Excitants, or stimulants, cause one’s body to be stimulated into a faster heartbeat and a faster metabolic rate. Hallucinogens cause people to see, hear, or feel sensations that are not real.

Two commonly used stimulant drugs are tobacco and caffeine. Hypnotics include mescaline (mushrooms). Hallucinogens include peyote, agaric, marijuana, and morning glory. Euphorics include coca (rich in cocaine) and opium (morphine, codeine). These drugs can be useful to doctors because many relieve symptoms or pain of diseases. However, if misused, drugs can become harmful to one’s body and general health.


  1. Discussing illicit drugs with students is sometimes difficult. Begin the discussion by stating that there are substances derived from plants that can help us and there are those that can hurt us. Use the information in the Background section to help you introduce some of the helpful and hurtful drugs.
  2. Unfortunately there are few good books to use with students that deal with the subject of drugs. There are some web sites that provide good solid information on drugs that come from plants. Below are some examples, but we highly recommend that you conduct a search using one of the available search engines.
Story of Aspirin.
Information on caffeine.
Information on cocaine.

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