<p>Adulteration is the altering of a specimen to mask the presence of drugs. This can be attempted by several methods, such as:</p>
<ul>
<li>Dilution, in which other fluids are introduced into the specimen to reduce the concentration of drugs.</li>
<li>Addition, in which chemicals or elements such as bleach, vinegar, eye drops, apple juice or soap are introduced to mask the presence of drugs.</li>
<li>Substitution, in which an attempt is made to substitute a urine specimen from another person or an animal.</li>
</ul>

