In any drug case the prosecution must prove beyond a reasonable doubt that the substance at issue was in fact an illegal drug. The Texas Controlled Substances Act sets out four classes, or "Penalty Groups," of illegal substances with an extensive list of various drugs, medications and chemical compounds under each group. Penalties vary depending on the dangerousness of the substance and the amount possessed, trafficked or manufactured. Marijuana is not included in any of the penalty groups but has a classification of its own.
In Texas, we have some of the toughest state drug laws in the country. Possession of as little as two ounces or less of marijuana is a Class B misdemeanor which can result in a jail sentence of 180 days and a $10,000 fine. Possession of over 2,000 pounds of marijuana can lead to a sentence of life in prison. For other drugs, depending on the quantity involved, charges for possession can range from a Class B misdemeanor to a first degree felony. Trafficking, cultivating or manufacturing drugs in Texas are also punishable by very harsh sentences.
With penalties like these, anyone facing state drug charges in Texas can benefit from an aggressive defense. If laboratory or other tests show the substance at issue was not in fact one of the substances set forth in the Controlled Substances Act, the charges can be dismissed. Other defenses include lack of knowledge, if the defendant was unaware the illegal drug was in his or her possession, or an insufficient quantity of the substance to justify the charge in question. Additional defenses might entail a valid prescription for the substance or a legally recognized justification to possess the substance for some purpose other than human consumption.
Source: Findlaw, "Texas Drug Possession Laws," accessed Sept. 12, 2015