An employer is not only interested in optimal performance by the persons employed by him, but also in a trusted and good working atmosphere. Through the use of alcohol or other intoxicating substances, but it can be a benefit both quantitative and qualitative deterioration in the performance of work. The present work deals with the question of what restrictions the legislature has prescribed with respect to the use of alcohol or other intoxicating substances, and what options are granted to the employer, they continue going to design or substantiate. Likewise, some will be discussed for the employment relationship are particularly relevant offenses, which include for example the theft or embezzlement. Especially since any prohibitions and restrictions can only be successful if the employer is also able to monitor their observance, will be discussed in a chapter of this work to the level of control of the employer. Treated, what it needs to implement and when those are carried out in such intense form, that their legitimacy is not possible under any circumstances. In the penultimate part of this work, the possibilities of the employee, and they are in a contractual relationship such as the employment of particular importance, to oppose to intensive control measures of the employer to defend, run. Similarly, the AG are entitled to the response options, should the persons employed by him, its prohibitions do not obey a code or create the tag, which is contrary to its interests, briefly explained.